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@@ -1,2608 +1,1304 @@
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-<sect1 id="zend.db.select">
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- <title>Zend_Db_Select</title>
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- <sect2 id="zend.db.select.introduction">
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-
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-
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- <title>Visão Geral do Objeto Select</title>
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-
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-
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- <para>
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-
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- O objeto Zend_Db_Select representa um comando de consulta SQL <code>SELECT</code>.
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-
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- A classe possui métodos para a adição de partes individuais em uma query. Você
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-
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- pode especificar algumas partes da consulta usando métodos PHP e estruturas de
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- dados, e a classe se encarrega de formar a sintaxe SQL correta para você. Depois
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-
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- da construção de uma consulta, você pode executá-la como se você houvesse a escrito
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- em uma string.
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-
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- </para>
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-
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- <para>
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-
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- As vantagens oferecidas pelo Zend_Db_Select incluem:
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- </para>
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- <itemizedlist>
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- <listitem>
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-
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- <para>
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-
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- Métodos orientados a objetos para especificação de consultas SQL
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-
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- de maneira "piece-by-piece" (aos pedaços ou em partes);
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- </para>
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- </listitem>
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- <listitem>
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-
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- <para>
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-
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- Abstração de independência de base de dados de algumas partes
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- da consulta SQL;
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- </para>
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- </listitem>
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- <listitem>
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-
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- <para>
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- Colocação automática de aspas nos identificadores de metadados na maioria
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- dos casos, para dar suporte aos identificadores que contém palavras SQL reservadas
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- e caracteres especiais;
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- </para>
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- </listitem>
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- <listitem>
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- <para>
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- Colocação automática de aspas nos identificadores e valores, para ajudar
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- na redução de ataques por "SQL injection".
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-
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- </para>
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- </listitem>
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- </itemizedlist>
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- <para>
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- A utilização de Zend_Db_Select não é obrigatória. Para consultas SELECT
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-
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- muito simples, normalmente é mais fácil escrever toda a consulta SQL
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-
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- em uma string e executá-la usando métodos da classe Adapter, como o
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-
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- <code>query()</code> ou <code>fetchAll()</code>. O uso de Zend_Db_Select
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-
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- é muito útil quando você precisa montar uma consulta SELECT usando "procedures"
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- (através de procedimentos), ou quando você precisa montar a consulta baseando-se
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- na lógica condicional da sua aplicação.
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-
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- </para>
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- </sect2>
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- <sect2 id="zend.db.select.creating">
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-
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- <title>Criando um Objeto Select</title>
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- <para>
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- Você pode criar uma instância de um objeto Zend_Db_Select
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-
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- usando o método <code>select()</code> de um objeto Zend_Db_Adapter_Abstract.
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-
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- </para>
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- <example id="zend.db.select.creating.example-db">
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- <title>Exemplo do método select() do adaptador para bases de dados</title>
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- <programlisting role="php"><![CDATA[<?php
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-$db = Zend_Db::factory( ...options... );
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-$select = $db->select();]]></programlisting>
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-
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- </example>
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- <para>
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- Outra forma de criar um objeto Zend_Db_Select é com o
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-
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- construtor dele, especificando o adaptador como parâmetro.
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-
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- </para>
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- <example id="zend.db.select.creating.example-new">
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- <title>Examplo da criação de um novo objeto Select</title>
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- <programlisting role="php"><![CDATA[<?php
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-$db = Zend_Db::factory( ...options... );
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-$select = new Zend_Db_Select($db);]]></programlisting>
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-
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- </example>
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- </sect2>
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- <sect2 id="zend.db.select.building">
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- <title>Construindo Consultas Select</title>
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- <para>
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- Ao contruir um consulta, você pode adicionar cláusulas uma por uma.
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- Existe um método diferente para cada cláusula no objeto.
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- </para>
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- <example id="zend.db.select.building.example">
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- <title>Exemplo do uso de métodos para adicionar cláusulas</title>
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- <programlisting role="php"><![CDATA[<?php
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-// Create the Zend_Db_Select object
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-$select = $db->select();
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-
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-
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-// Add a FROM clause
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-$select->from( ...specify table and columns... )
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-// Add a WHERE clause
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-$select->where( ...specify search criteria... )
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-// Add an ORDER BY clause
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-$select->order( ...specify sorting criteria... );]]></programlisting>
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-
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- </example>
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- <para>
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- Você também pode usar a maior parte dos métodos do objeto Zend_Db_Select
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-
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- com uma interface "fluent" conveniente. Uma interface "fluent" significa que cada
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-
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- método retorna uma referência para o objeto no qual foi chamado, então você pode
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- imediatamente chamar outro método.
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- </para>
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- <example id="zend.db.select.building.example-fluent">
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- <title>Examplo de uso da interface "fluent"</title>
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- <programlisting role="php"><![CDATA[<?php
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-$select = $db->select()
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-
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- ->from( ...specify table and columns... )
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- ->where( ...specify search criteria... )
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- ->order( ...specify sorting criteria... );]]></programlisting>
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- </example>
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- <para>
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- Os exemplos nesta seção mostram o uso da interface "fluent",
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- mas você pode usar a interface "non-fluent" em todos os casos.
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- É freqüentemente necessário usar a interface "non-fluent" quando, por exemplo,
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- sua aplicação precisa executar alguma lógica antes de adicionar uma cláusula
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-
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- a uma consulta.
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-
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- </para>
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- <sect3 id="zend.db.select.building.from">
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- <title>Adicionando uma cláusula FROM</title>
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- <para>
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- Especifique a tabela para esta consulta usando o método <code>from()</code>.
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-
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- Você pode especificar o nome da tabela como uma simples string.
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- Zend_Db_Select coloca o entre aspas o nome da tabela, então, você pode
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- usar caracteres especiais.
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- </para>
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- <example id="zend.db.select.building.from.example">
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- <title>Example of the from() method</title>
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- <programlisting role="php"><![CDATA[<?php
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-// Build this query:
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-
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-// SELECT *
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-// FROM "products"
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-$select = $db->select()
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- ->from( 'products' );]]></programlisting>
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- </example>
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- <para>
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- You can also specify the correlation name (sometimes called the
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- "table alias") for a table. Instead of a simple string, use an
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- associative array mapping the correlation name to the table
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- name. In other clauses of the SQL query, use this correlation
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- name. If your query joins more than one table, Zend_Db_Select
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- generates unique correlation names based on the table names,
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- for any tables for which you don't specify the correlation name.
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-
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- </para>
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- <example id="zend.db.select.building.from.example-cname">
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- <title>Example of specifying a table correlation name</title>
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- <programlisting role="php"><![CDATA[<?php
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-// Build this query:
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-
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-// SELECT p.*
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-// FROM "products" AS p
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-$select = $db->select()
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-
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- ->from( array('p' => 'products') );]]></programlisting>
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-
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- </example>
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-
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-
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- <para>
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- Algumas marcas de RDBMS dão suporte a um especificador de schema
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- para uma tabela. Você pode especificar o nome a tabela como
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-
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- "<code>schemaName.tableName</code>", onde Zend_Db_Select coloca entre aspas
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-
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- cada uma das partes individualmente, ou então você deve especificar o nome
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-
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- do schema separadamente. Um nome de schema especificado no nome da tabela
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- precede um schema fornecido separadamente se eventualmente ambos forem
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-
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- informados.
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- </para>
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- <example id="zend.db.select.building.from.example-schema">
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- <title>Exemplo de especificação de nome de schema</title>
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- <programlisting role="php"><![CDATA[<?php
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-// Build this query:
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-// SELECT *
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-// FROM "myschema"."products"
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-$select = $db->select()
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- ->from( 'myschema.products' );
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-// or
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-$select = $db->select()
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- ->from('products', '*', 'myschema');]]></programlisting>
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- </example>
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- </sect3>
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- <sect3 id="zend.db.select.building.columns">
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- <title>Adicionando Colunas</title>
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-
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- <para>
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- No segundo argumento do método <code>from()</code> ,
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-
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- você pode especificaras colunas a serem selecionadas da
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- respectiva tabela. Se você não especificar nenhuma coluna,
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-
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- o valor padrão é "<code>*</code>", o caracter curinga para "todas as colunas".
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-
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- </para>
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-
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- <para>
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- Você pode listar as colunas em um simples array de strings, ou como
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-
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- um mapeamento associativo do alias da coluna para nome da coluna.
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- Se você só tiver uma coluna para consultar, e não precisar indicar um
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-
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- alias, você pode listá-la em uma string simples ao invés de um array.
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-
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- </para>
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- <para>
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- Se você passar um array vazio como o argumento de colunas, nenhuma
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-
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- coluna da respectiva tabela será incluída no result set.
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-
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- Veja um exemplo de <link linkend="zend.db.select.building.join.example-no-columns">código</link> sob a seção do método <code>join()</code>.
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-
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- </para>
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- <para>
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- Você pode especificar o nome da coluna como
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-
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- "<code>correlationName.columnName</code>".
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-
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- Zend_Db_Select os coloca entre aspas individualmente.
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|
- Caso você não especifique o nome da correlação para uma coluna,
|
|
|
-
|
|
|
- é usado o nome da correlação da tabela indicada no método<code>from()</code>.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.columns.example">
|
|
|
-
|
|
|
- <title>Examples of specifying columns</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'product_name'));
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build the same query, specifying correlation names:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('p.product_id', 'p.product_name'));
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query with an alias for one column:
|
|
|
-
|
|
|
-// SELECT p."product_id" AS prodno, p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('prodno' => 'product_id', 'product_name'));]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.columns-expr">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adicionando Colunas de Expressões</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Algumas vezes as colunas de uma consulta SQL são expressões, e não
|
|
|
-
|
|
|
- simplesmente o nome de uma couna da tabela. Expressões não devem usar
|
|
|
-
|
|
|
- nomes de correlação ou aspas. Se a string da coluna possuir parênteses,
|
|
|
-
|
|
|
- Zend_Db_Select a reconhecerá como uma expressão.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Você também pode criar um objeto do tipo Zend_Db_Expr explicitamente,
|
|
|
-
|
|
|
- para prevenir que uma string seja tratada como um nome de coluna.
|
|
|
-
|
|
|
- Zend_Db_Expr é uma classe diminuta que contém uma única string.
|
|
|
-
|
|
|
- Zend_Db_Select reconhece obtejos do tipo Zend_Db_Expr e os converte
|
|
|
-
|
|
|
- novamente para strings, mas não efetua qualquer alteração como a
|
|
|
-
|
|
|
- colocação de aspas ou nomes de correlação.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <note>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- O uso de Zend_Db_Expr para nomes de colunas não é necessário se as
|
|
|
-
|
|
|
- expressões contiverem parênteses; Zend_Db_Select reconhece os parênteses
|
|
|
-
|
|
|
- e trata a string como uma expresão, ignorando a colocação de aspas e de
|
|
|
-
|
|
|
- nomes de correlação.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </note>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.columns-expr.example">
|
|
|
-
|
|
|
- <title>Exemplos de especificação de colunas contendo expressões</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", LOWER(product_name)
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-// An expression with parentheses implicitly becomes
|
|
|
-
|
|
|
-// a Zend_Db_Expr.
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'LOWER(product_name)'));
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", (p.cost * 1.08) AS cost_plus_tax
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'cost_plus_tax' => '(p.cost * 1.08)'));
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query using Zend_Db_Expr explicitly:
|
|
|
-
|
|
|
-// SELECT p."product_id", p.cost * 1.08 AS cost_plus_tax
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'cost_plus_tax' => new Zend_Db_Expr('p.cost * 1.08')));]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Nos casos acima, Zend_Db_Select não altera a string
|
|
|
-
|
|
|
- para colocar os nomes de correlação ou aspas. Se as
|
|
|
-
|
|
|
- mudanças forem necessárias para evitar alguma ambiguidade,
|
|
|
-
|
|
|
- você deve fazê-las manualmente na string.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Se os nomes das colunas são palavras-chave SQL ou possuem
|
|
|
-
|
|
|
- caracteres especiais, você deve usar o método <code>quoteIdentifier()</code>
|
|
|
-
|
|
|
- da classe Adapter, e interpolar o resultado na string. O método
|
|
|
-
|
|
|
- <code>quoteIdentifier()</code> usa aspas no SQL para delimitar o identificador,
|
|
|
-
|
|
|
- o que deixa claro que ele é um identificador de uma tabela ou coluna e não
|
|
|
-
|
|
|
- parte da síntaxe SQL.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Seu código fica mais independente de base de dados se você
|
|
|
-
|
|
|
- usar o método <code>quoteIdentifier()</code> ao invés de digitar
|
|
|
-
|
|
|
- as aspas nas strings porque algumas marcas de SGBD Relacionais usam
|
|
|
-
|
|
|
- símbolos fora do padrão para referenciar identificadores.
|
|
|
-
|
|
|
- O método <code>quoteIdentifier()</code> é projetado para usar
|
|
|
-
|
|
|
- os símbolos de referência apropriados de acordo com o tipo de adaptador.
|
|
|
-
|
|
|
- O método <code>quoteIdentifier()</code> também ignora qualquer
|
|
|
-
|
|
|
- caracter de referência que aparecer no nome de um identificador.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.columns-quoteid.example">
|
|
|
-
|
|
|
- <title>Examples of quoting columns in an expression</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query, quoting a special column name "from" in the expression:
|
|
|
-
|
|
|
-// SELECT p."from" + 10 AS origin
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('origin' => '(p.' . $db->quoteIdentifier('from') . ' + 10)'));]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.join">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding Another Table to the Query with JOIN</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Many useful queries involve using a <code>JOIN</code>
|
|
|
-
|
|
|
- to combine rows from multiple tables. You can add
|
|
|
-
|
|
|
- tables to a Zend_Db_Select query using the
|
|
|
-
|
|
|
- <code>join()</code> method. Using this method is
|
|
|
-
|
|
|
- similar to the <code>from()</code> method, except
|
|
|
-
|
|
|
- you can also specify a join condition in most cases.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.join.example">
|
|
|
-
|
|
|
- <title>Example of the join() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name", l.*
|
|
|
-
|
|
|
-// FROM "products" AS p JOIN "line_items" AS l
|
|
|
-
|
|
|
-// ON p.product_id = l.product_id
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'product_name'))
|
|
|
-
|
|
|
- ->join(array('l' => 'line_items'),
|
|
|
-
|
|
|
- 'p.product_id = l.product_id');]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The second argument to <code>join()</code> is a string
|
|
|
-
|
|
|
- that is the join condition. This is an expression that
|
|
|
-
|
|
|
- declares the criteria by which rows in one table match
|
|
|
-
|
|
|
- rows in the the other table. You can use correlation
|
|
|
-
|
|
|
- names in this expression.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <note>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- No quoting is applied to the expression you specify
|
|
|
-
|
|
|
- for the join condition; if you have column names that need
|
|
|
-
|
|
|
- to be quoted, you must use <code>quoteIdentifier()</code>
|
|
|
-
|
|
|
- as you form the string for the join condition.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </note>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The third argument to <code>join()</code> is an array
|
|
|
-
|
|
|
- of column names, like that used in the <code>from()</code>
|
|
|
-
|
|
|
- method. It defaults to "<code>*</code>", supports correlation
|
|
|
-
|
|
|
- names, expressions, and Zend_Db_Expr in the same way as the
|
|
|
-
|
|
|
- array of column names in the <code>from()</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- To select no columns from a table, use an empty array for
|
|
|
-
|
|
|
- the list of columns. This usage works in the
|
|
|
-
|
|
|
- <code>from()</code> method too, but typically you want
|
|
|
-
|
|
|
- some columns from the primary table in your queries,
|
|
|
-
|
|
|
- whereas you might want no columns from a joined table.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.join.example-no-columns">
|
|
|
-
|
|
|
- <title>Example of specifying no columns</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p JOIN "line_items" AS l
|
|
|
-
|
|
|
-// ON p.product_id = l.product_id
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id', 'product_name'))
|
|
|
-
|
|
|
- ->join(array('l' => 'line_items'),
|
|
|
-
|
|
|
- 'p.product_id = l.product_id',
|
|
|
-
|
|
|
- array() ); // empty list of columns]]></programlisting>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Note the empty <code>array()</code> in the above example
|
|
|
-
|
|
|
- in place of a list of columns from the joined table.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- SQL has several types of joins.
|
|
|
-
|
|
|
- See the list below for the methods to support
|
|
|
-
|
|
|
- different join types in Zend_Db_Select.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <itemizedlist>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>INNER JOIN</command> with the
|
|
|
-
|
|
|
- <code>join(table, join, [columns])</code>
|
|
|
-
|
|
|
- or <code>joinInner(table, join, [columns])</code> methods.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- This may be the most common type of join. Rows from
|
|
|
-
|
|
|
- each table are compared using the join condition you
|
|
|
-
|
|
|
- specify. The result set includes only the rows that
|
|
|
-
|
|
|
- satisfy the join condition. The result set can be
|
|
|
-
|
|
|
- empty if no rows satisfy this condition.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- All RDBMS brands support this join type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>LEFT JOIN</command> with the
|
|
|
-
|
|
|
- <code>joinLeft(table, condition, [columns])</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- All rows from the left operand table are included,
|
|
|
-
|
|
|
- matching rows from the right operand table included,
|
|
|
-
|
|
|
- and the columns from the right operand table are filled
|
|
|
-
|
|
|
- with NULLs if no row exists matching the left table.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- All RDBMS brands support this join type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>RIGHT JOIN</command> with the
|
|
|
-
|
|
|
- <code>joinRight(table, condition, [columns])</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Right outer join is the complement of left outer join.
|
|
|
-
|
|
|
- All rows from the right operand table are included,
|
|
|
-
|
|
|
- matching rows from the left operand table included,
|
|
|
-
|
|
|
- and the columns from the left operand table are filled
|
|
|
-
|
|
|
- with NULLs if no row exists matching the right table.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Some RDBMS brands don't support this join type, but
|
|
|
-
|
|
|
- in general any right join can be represented as a left
|
|
|
-
|
|
|
- join by reversing the order of the tables.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>FULL JOIN</command> with the
|
|
|
-
|
|
|
- <code>joinFull(table, condition, [columns])</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- A full outer join is like combining a left outer join
|
|
|
-
|
|
|
- and a right outer join. All rows from both tables are
|
|
|
-
|
|
|
- included, paired with each other on the same row of the
|
|
|
-
|
|
|
- result set if they satisfy the join condition, and
|
|
|
-
|
|
|
- otherwise paired with NULLs in place of columns from the
|
|
|
-
|
|
|
- other table.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Some RDBMS brands don't support this join type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>CROSS JOIN</command> with the
|
|
|
-
|
|
|
- <code>joinCross(table, [columns])</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- A cross join is a Cartesian product.
|
|
|
-
|
|
|
- Every row in the first table is matched to every
|
|
|
-
|
|
|
- row in the second table. Therefore the number of
|
|
|
-
|
|
|
- rows in the result set is equal to the product of
|
|
|
-
|
|
|
- the number of rows in each table. You can filter
|
|
|
-
|
|
|
- the result set using conditions in a WHERE clause;
|
|
|
-
|
|
|
- in this way a cross join is similar to the old SQL-89
|
|
|
-
|
|
|
- join syntax.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>joinCross()</code> method has no parameter
|
|
|
-
|
|
|
- to specify the join condition.
|
|
|
-
|
|
|
- Some RDBMS brands don't support this join type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- <listitem>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- <command>NATURAL JOIN</command> with the
|
|
|
-
|
|
|
- <code>joinNatural(table, [columns])</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- A natural join compares any column(s) that appear with
|
|
|
-
|
|
|
- the same name in both tables. The comparison is
|
|
|
-
|
|
|
- equality of all the column(s); comparing the columns
|
|
|
-
|
|
|
- using inequality is not a natural join.
|
|
|
-
|
|
|
- Only natural inner joins are supported by this API,
|
|
|
-
|
|
|
- even though SQL permits natural outer joins as well.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>joinNatural()</code> method has no parameter
|
|
|
-
|
|
|
- to specify the join condition.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </listitem>
|
|
|
-
|
|
|
- </itemizedlist>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.where">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding a WHERE Clause</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- You can specify criteria for restricting rows of the result set
|
|
|
-
|
|
|
- using the <code>where()</code> method. The first argument of
|
|
|
-
|
|
|
- this method is a SQL expression, and this expression is used
|
|
|
-
|
|
|
- in a SQL <code>WHERE</code> clause in the query.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.where.example">
|
|
|
-
|
|
|
- <title>Example of the where() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT product_id, product_name, price
|
|
|
-
|
|
|
-// FROM "products"
|
|
|
-
|
|
|
-// WHERE price > 100.00
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(
|
|
|
-
|
|
|
- 'products',
|
|
|
-
|
|
|
- array('product_id', 'product_name', 'price'))
|
|
|
-
|
|
|
- ->where('price > 100.00');]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <note>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- No quoting is applied to expressions given to the
|
|
|
-
|
|
|
- <code>where()</code> or <code>orWhere()</code> methods.
|
|
|
-
|
|
|
- If you have column names that need to be quoted, you must use
|
|
|
-
|
|
|
- <code>quoteIdentifier()</code> as you form the string for the
|
|
|
-
|
|
|
- condition.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </note>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The second argument to the <code>where()</code> method is
|
|
|
-
|
|
|
- optional. It is a value to substitute into the expression.
|
|
|
-
|
|
|
- Zend_Db_Select quotes the value and substitutes it for a
|
|
|
-
|
|
|
- question-mark ("<code>?</code>") symbol in the expression.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- This method accepts only one parameter.
|
|
|
-
|
|
|
- If you have an expression into which you need to substitute
|
|
|
-
|
|
|
- multiple variables, you must format the string manually,
|
|
|
-
|
|
|
- interpolating variables and performing quoting yourself.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.where.example-param">
|
|
|
-
|
|
|
- <title>Example of a parameter in the where() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT product_id, product_name, price
|
|
|
-
|
|
|
-// FROM "products"
|
|
|
-
|
|
|
-// WHERE (price > 100.00)
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$minimumPrice = 100;
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(
|
|
|
-
|
|
|
- 'products',
|
|
|
-
|
|
|
- array('product_id', 'product_name', 'price'))
|
|
|
-
|
|
|
- ->where('price > ?', $minimumPrice);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- You can invoke the <code>where()</code> method multiple times
|
|
|
-
|
|
|
- on the same Zend_Db_Select object. The resulting query combines
|
|
|
-
|
|
|
- the multiple terms together using <code>AND</code> between them.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.where.example-and">
|
|
|
-
|
|
|
- <title>Example of multiple where() methods</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT product_id, product_name, price
|
|
|
-
|
|
|
-// FROM "products"
|
|
|
-
|
|
|
-// WHERE (price > 100.00)
|
|
|
-
|
|
|
-// AND (price < 500.00)
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$minimumPrice = 100;
|
|
|
-
|
|
|
-$maximumPrice = 500;
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products',
|
|
|
-
|
|
|
- array('product_id', 'product_name', 'price'))
|
|
|
-
|
|
|
- ->where('price > ?', $minimumPrice)
|
|
|
-
|
|
|
- ->where('price < ?', $maximumPrice);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- If you need to combine terms together using <code>OR</code>,
|
|
|
-
|
|
|
- use the <code>orWhere()</code> method. This method is used
|
|
|
-
|
|
|
- in the same way as the <code>where()</code> method, except
|
|
|
-
|
|
|
- that the term specified is preceded by <code>OR</code>,
|
|
|
-
|
|
|
- instead of <code>AND</code>.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.where.example-or">
|
|
|
-
|
|
|
- <title>Example of the orWhere() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT product_id, product_name, price
|
|
|
-
|
|
|
-// FROM "products"
|
|
|
-
|
|
|
-// WHERE (price < 100.00)
|
|
|
-
|
|
|
-// OR (price > 500.00)
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$minimumPrice = 100;
|
|
|
-
|
|
|
-$maximumPrice = 500;
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products',
|
|
|
-
|
|
|
- array('product_id', 'product_name', 'price'))
|
|
|
-
|
|
|
- ->where('price < ?', $minimumPrice)
|
|
|
-
|
|
|
- ->orWhere('price > ?', $maximumPrice);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Zend_Db_Select automatically puts parentheses around each
|
|
|
-
|
|
|
- expression you specify using the <code>where()</code> or
|
|
|
-
|
|
|
- <code>orWhere()</code> methods. This helps to ensure that
|
|
|
-
|
|
|
- Boolean operator precedence does not cause unexpected
|
|
|
-
|
|
|
- results.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.where.example-parens">
|
|
|
-
|
|
|
- <title>Example of parenthesizing Boolean expressions</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT product_id, product_name, price
|
|
|
-
|
|
|
-// FROM "products"
|
|
|
-
|
|
|
-// WHERE (price < 100.00 OR price > 500.00)
|
|
|
-
|
|
|
-// AND (product_name = 'Apple')
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$minimumPrice = 100;
|
|
|
-
|
|
|
-$maximumPrice = 500;
|
|
|
-
|
|
|
-$prod = 'Apple';
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products',
|
|
|
-
|
|
|
- array('product_id', 'product_name', 'price'))
|
|
|
-
|
|
|
- ->where("price < $minimumPrice OR price > $maximumPrice")
|
|
|
-
|
|
|
- ->where('product_name = ?', $prod);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In the example above, the results would be quite different
|
|
|
-
|
|
|
- without the parentheses, because <code>AND</code> has higher
|
|
|
-
|
|
|
- precedence than <code>OR</code>. Zend_Db_Select applies the
|
|
|
-
|
|
|
- parentheses so the effect is that each expression in successive
|
|
|
-
|
|
|
- calls to the <code>where()</code> bind more tightly than the
|
|
|
-
|
|
|
- <code>AND</code> that combines the expressions.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.group">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding a GROUP BY Clause</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In SQL, the <code>GROUP BY</code> clause allows you
|
|
|
-
|
|
|
- to reduce the rows of a query result set to one row per
|
|
|
-
|
|
|
- unique value found in the column(s) named in the
|
|
|
-
|
|
|
- <code>GROUP BY</code> clause.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In Zend_Db_Select, you can specify the column(s) to use
|
|
|
-
|
|
|
- for calculating the groups of rows using the
|
|
|
-
|
|
|
- <code>group()</code> method. The argument to this
|
|
|
-
|
|
|
- method is a column or an array of columns to use in
|
|
|
-
|
|
|
- the <code>GROUP BY</code> clause.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.group.example">
|
|
|
-
|
|
|
- <title>Example of the group() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
-
|
|
|
-// FROM "products" AS p JOIN "line_items" AS l
|
|
|
-
|
|
|
-// ON p.product_id = l.product_id
|
|
|
-
|
|
|
-// GROUP BY p.product_id
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id'))
|
|
|
-
|
|
|
- ->join(array('l' => 'line_items'),
|
|
|
-
|
|
|
- 'p.product_id = l.product_id',
|
|
|
-
|
|
|
- array('line_items_per_product' => 'COUNT(*)'))
|
|
|
-
|
|
|
- ->group('p.product_id');]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Like the columns array in the <code>from()</code> method, you
|
|
|
-
|
|
|
- can use correlation names in the column name strings, and the
|
|
|
-
|
|
|
- column is quoted as an identifier unless the string contains
|
|
|
-
|
|
|
- parentheses or is an object of type Zend_Db_Expr.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.having">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding a HAVING Clause</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In SQL, the <code>HAVING</code> clause applies a restriction
|
|
|
-
|
|
|
- condition on groups of rows. This is similar to how a
|
|
|
-
|
|
|
- <code>WHERE</code> clause applies a restriction condition on rows.
|
|
|
-
|
|
|
- But the two clauses are different because <code>WHERE</code>
|
|
|
-
|
|
|
- conditions are applied before groups are defined, whereas
|
|
|
-
|
|
|
- <code>HAVING</code> conditions are applied after groups are
|
|
|
-
|
|
|
- defined.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In Zend_Db_Select, you can specify conditions for restricting
|
|
|
-
|
|
|
- groups using the <code>having()</code> method. Its usage is
|
|
|
-
|
|
|
- similar to that of the <code>where()</code> method.
|
|
|
-
|
|
|
- The first argument is a string containing a SQL expression.
|
|
|
-
|
|
|
- The optional second argument is a value that is used to replace
|
|
|
-
|
|
|
- a positional parameter placeholder in the SQL expression.
|
|
|
-
|
|
|
- Expressions given in multiple invocations of the
|
|
|
-
|
|
|
- <code>having()</code> method are combined using the Boolean
|
|
|
-
|
|
|
- <code>AND</code> operator, or the <code>OR</code> operator if
|
|
|
-
|
|
|
- you use the <code>orHaving()</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.having.example">
|
|
|
-
|
|
|
- <title>Example of the having() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
-
|
|
|
-// FROM "products" AS p JOIN "line_items" AS l
|
|
|
-
|
|
|
-// ON p.product_id = l.product_id
|
|
|
-
|
|
|
-// GROUP BY p.product_id
|
|
|
-
|
|
|
-// HAVING line_items_per_product > 10
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id'))
|
|
|
-
|
|
|
- ->join(array('l' => 'line_items'),
|
|
|
-
|
|
|
- 'p.product_id = l.product_id',
|
|
|
-
|
|
|
- array('line_items_per_product' => 'COUNT(*)'))
|
|
|
-
|
|
|
- ->group('p.product_id')
|
|
|
-
|
|
|
- ->having('line_items_per_product > 10');]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <note>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- No quoting is applied to expressions given to the
|
|
|
-
|
|
|
- <code>having()</code> or <code>orHaving()</code> methods.
|
|
|
-
|
|
|
- If you have column names that need to be quoted, you must use
|
|
|
-
|
|
|
- <code>quoteIdentifier()</code> as you form the string for the
|
|
|
-
|
|
|
- condition.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </note>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.order">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding an ORDER BY Clause</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In SQL, the <code>ORDER BY</code> clause specifies one or more
|
|
|
-
|
|
|
- columns or expressions by which the result set of a query is
|
|
|
-
|
|
|
- sorted. If multiple columns are listed, the secondary columns
|
|
|
-
|
|
|
- are used to resolve ties; the sort order is determined by the
|
|
|
-
|
|
|
- secondary columns if the preceding columns contain identical
|
|
|
-
|
|
|
- values. The default sorting is from least value to greatest
|
|
|
-
|
|
|
- value. You can also sort by greatest value to least value for
|
|
|
-
|
|
|
- a given column in the list by specifying the keyword
|
|
|
-
|
|
|
- <code>DESC</code> after that column.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In Zend_Db_Select, you can use the <code>order()</code> method
|
|
|
-
|
|
|
- to specify a column or an array of columns by which to sort.
|
|
|
-
|
|
|
- Each element of the array is a string naming a column.
|
|
|
-
|
|
|
- optionally with the <code>ASC</code> <code>DESC</code> keyword
|
|
|
-
|
|
|
- following it, separated by a space.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Like in the <code>from()</code> and <code>group()</code>
|
|
|
-
|
|
|
- methods, column names are quoted as identifiers, unless they
|
|
|
-
|
|
|
- contain contain parentheses or are an object of type
|
|
|
-
|
|
|
- Zend_Db_Expr.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.order.example">
|
|
|
-
|
|
|
- <title>Example of the order() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
-
|
|
|
-// FROM "products" AS p JOIN "line_items" AS l
|
|
|
-
|
|
|
-// ON p.product_id = l.product_id
|
|
|
-
|
|
|
-// GROUP BY p.product_id
|
|
|
-
|
|
|
-// ORDER BY "line_items_per_product" DESC, "product_id"
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'),
|
|
|
-
|
|
|
- array('product_id'))
|
|
|
-
|
|
|
- ->join(array('l' => 'line_items'),
|
|
|
-
|
|
|
- 'p.product_id = l.product_id',
|
|
|
-
|
|
|
- array('line_items_per_product' => 'COUNT(*)'))
|
|
|
-
|
|
|
- ->group('p.product_id')
|
|
|
-
|
|
|
- ->order(array('line_items_per_product DESC', 'product_id'));]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.limit">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding a LIMIT Clause</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Some RDBMS brands extend SQL with a query clause known as the
|
|
|
-
|
|
|
- <code>LIMIT</code> clause. This clause reduces the number of
|
|
|
-
|
|
|
- rows in the result set to at most a number you specify.
|
|
|
-
|
|
|
- You can also specify to skip a number of rows before starting
|
|
|
-
|
|
|
- to output.
|
|
|
-
|
|
|
- This feature makes it easy to take a subset of a result set,
|
|
|
-
|
|
|
- for example when displaying query results on progressive pages
|
|
|
-
|
|
|
- of output.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- In Zend_Db_Select, you can use the <code>limit()</code> method
|
|
|
-
|
|
|
- to specify the count of rows and the number of rows to skip.
|
|
|
-
|
|
|
- The first argument to this method is the desired count of rows.
|
|
|
-
|
|
|
- The second argument is the number of rows to skip.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.limit.example">
|
|
|
-
|
|
|
- <title>Example of the limit() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-// LIMIT 10, 20
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'), array('product_id', 'product_name'))
|
|
|
-
|
|
|
- ->limit(10, 20);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <note>
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>LIMIT</code> syntax is not supported by all RDBMS
|
|
|
-
|
|
|
- brands. Some RDBMS require different syntax to support
|
|
|
-
|
|
|
- similar functionality. Each Zend_Db_Adapter_Abstract class
|
|
|
-
|
|
|
- includes a method to produce SQL appropriate for that RDBMS.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
- </note>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- Use the <code>limitPage()</code> method for an alternative way
|
|
|
-
|
|
|
- to specify row count and offset. This method allows you to
|
|
|
-
|
|
|
- limit the result set to one of a series of fixed-length subsets
|
|
|
-
|
|
|
- of rows from the query's total result set. In other words, you
|
|
|
-
|
|
|
- specify the length of a "page" of results, and the ordinal
|
|
|
-
|
|
|
- number of the single page of results you want the query to return.
|
|
|
-
|
|
|
- The page number is the first argument of the
|
|
|
-
|
|
|
- <code>limitPage()</code> method, and the page length is the
|
|
|
-
|
|
|
- second argument. Both arguments are required; they have no
|
|
|
-
|
|
|
- default values.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.limit.example2">
|
|
|
-
|
|
|
- <title>Example of the limitPage() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT p."product_id", p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-// LIMIT 10, 20
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'), array('product_id', 'product_name'))
|
|
|
-
|
|
|
- ->limitPage(2, 10);]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.distinct">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding the DISTINCT Query Modifier</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>distinct()</code> method enables you to add the
|
|
|
-
|
|
|
- <code>DISTINCT</code> keyword to your SQL query.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.distinct.example">
|
|
|
-
|
|
|
- <title>Example of the distinct() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT DISTINCT p."product_name"
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->distinct()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'), 'product_name');]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.building.for-update">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Adding the FOR UPDATE Query Modifier</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>forUpdate()</code> method enables you to add the
|
|
|
-
|
|
|
- <code>FOR UPDATE</code> modifier to your SQL query.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.building.for-update.example">
|
|
|
-
|
|
|
- <title>Example of forUpdate() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Build this query:
|
|
|
-
|
|
|
-// SELECT FOR UPDATE p.*
|
|
|
-
|
|
|
-// FROM "products" AS p
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->forUpdate()
|
|
|
-
|
|
|
- ->from(array('p' => 'products'));]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
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-
|
|
|
-
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|
|
-
|
|
|
- </sect3>
|
|
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-
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-
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|
-
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|
|
- </sect2>
|
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-
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-
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|
-
|
|
|
- <sect2 id="zend.db.select.execute">
|
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-
|
|
|
-
|
|
|
-
|
|
|
- <title>Executing Select Queries</title>
|
|
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-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- This section describes how to execute the query represented by a
|
|
|
-
|
|
|
- Zend_Db_Select object.
|
|
|
-
|
|
|
- </para>
|
|
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-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.execute.query-adapter">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Executing Select Queries from the Db Adapter</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- You can execute the query represented by the Zend_Db_Select
|
|
|
-
|
|
|
- object by passing it as the first argument to the
|
|
|
-
|
|
|
- <code>query()</code> method of a Zend_Db_Adapter_Abstract
|
|
|
-
|
|
|
- object. Use the Zend_Db_Select objects instead of a string
|
|
|
-
|
|
|
- query.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>query()</code> method returns an object of type
|
|
|
-
|
|
|
- Zend_Db_Statement or PDOStatement, depending on the adapter type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.execute.query-adapter.example">
|
|
|
-
|
|
|
- <title>Example using the Db adapter's query() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products');
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$stmt = $db->query($select);
|
|
|
-
|
|
|
-$result = $stmt->fetchAll();]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.execute.query-select">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Executing Select Queries from the Object</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- As an alternative to using the <code>query()</code> method
|
|
|
-
|
|
|
- of the adapter object, you can use the <code>query()</code>
|
|
|
-
|
|
|
- method of the Zend_Db_Select object.
|
|
|
-
|
|
|
- Both methods return an object of type Zend_Db_Statement or
|
|
|
-
|
|
|
- PDOStatement, depending on the adapter type.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.execute.query-select.example">
|
|
|
-
|
|
|
- <title>Example using the Select object's query method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products');
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$stmt = $select->query();
|
|
|
-
|
|
|
-$result = $stmt->fetchAll();]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.execute.tostring">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Converting a Select Object to a SQL String</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- If you need access to a string representation of the SQL
|
|
|
-
|
|
|
- query corresponding to the Zend_Db_Select object, use
|
|
|
-
|
|
|
- the <code>__toString()</code> method.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.execute.tostring.example">
|
|
|
-
|
|
|
- <title>Example of the __toString() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products');
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$sql = $select->__toString();
|
|
|
-
|
|
|
-echo "$sql\n";
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// The output is the string:
|
|
|
-
|
|
|
-// SELECT * FROM "products"]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect2>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect2 id="zend.db.select.other">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Other methods</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- This section describes other methods of the Zend_Db_Select class
|
|
|
-
|
|
|
- that are not covered above: <code>getPart()</code> and
|
|
|
-
|
|
|
- <code>reset()</code>.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.other.get-part">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Retrieving Parts of the Select Object</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>getPart()</code> method returns a representation
|
|
|
-
|
|
|
- of one part of your SQL query. For example, you can use this
|
|
|
-
|
|
|
- method to return the array of expressions for the
|
|
|
-
|
|
|
- <code>WHERE</code> clause, or the array of columns
|
|
|
-
|
|
|
- (or column expressions) that are in the <code>SELECT</code>
|
|
|
-
|
|
|
- list, or the values of the count and offset for the
|
|
|
-
|
|
|
- <code>LIMIT</code> clause.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The return value is not a string containing a fragment of SQL
|
|
|
-
|
|
|
- syntax. The return value is an internal representation, which
|
|
|
-
|
|
|
- is typically an array structure containing values and
|
|
|
-
|
|
|
- expressions. Each part of the query has a different structure.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The single argument to the <code>getPart()</code> method is
|
|
|
-
|
|
|
- a string that identifies which part of the Select query to
|
|
|
-
|
|
|
- return. For example, the string <code>'from'</code>
|
|
|
-
|
|
|
- identifies the part of the Select object that stores
|
|
|
-
|
|
|
- information about the tables in the <code>FROM</code> clause,
|
|
|
-
|
|
|
- including joined tables.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The Zend_Db_Select class defines constants you can use for
|
|
|
-
|
|
|
- parts of the SQL query. You can use these constant definitions,
|
|
|
-
|
|
|
- or you can the literal strings.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <table id="zend.db.select.other.get-part.table">
|
|
|
-
|
|
|
- <title>Constants used by getPart() and reset()</title>
|
|
|
-
|
|
|
- <tgroup cols="2">
|
|
|
-
|
|
|
- <thead>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry>Constant</entry>
|
|
|
-
|
|
|
- <entry>String value</entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- </thead>
|
|
|
-
|
|
|
- <tbody>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::DISTINCT</code></entry>
|
|
|
-
|
|
|
- <entry><code>'distinct'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::FOR_UPDATE</code></entry>
|
|
|
-
|
|
|
- <entry><code>'forupdate'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::COLUMNS</code></entry>
|
|
|
-
|
|
|
- <entry><code>'columns'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::FROM</code></entry>
|
|
|
-
|
|
|
- <entry><code>'from'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::WHERE</code></entry>
|
|
|
-
|
|
|
- <entry><code>'where'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::GROUP</code></entry>
|
|
|
-
|
|
|
- <entry><code>'group'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::HAVING</code></entry>
|
|
|
-
|
|
|
- <entry><code>'having'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::ORDER</code></entry>
|
|
|
-
|
|
|
- <entry><code>'order'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::LIMIT_COUNT</code></entry>
|
|
|
-
|
|
|
- <entry><code>'limitcount'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- <row>
|
|
|
-
|
|
|
- <entry><code>Zend_Db_Select::LIMIT_OFFSET</code></entry>
|
|
|
-
|
|
|
- <entry><code>'limitoffset'</code></entry>
|
|
|
-
|
|
|
- </row>
|
|
|
-
|
|
|
- </tbody>
|
|
|
-
|
|
|
- </tgroup>
|
|
|
-
|
|
|
- </table>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <example id="zend.db.select.other.get-part.example">
|
|
|
-
|
|
|
- <title>Example of the getPart() method</title>
|
|
|
-
|
|
|
- <programlisting role="php"><![CDATA[<?php
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-$select = $db->select()
|
|
|
-
|
|
|
- ->from('products')
|
|
|
-
|
|
|
- ->order('product_id');
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// You can use a string literal to specify the part
|
|
|
-
|
|
|
-$orderData = $select->getPart( 'order' );
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// You can use a constant to specify the same part
|
|
|
-
|
|
|
-$orderData = $select->getPart( Zend_Db_Select::ORDER );
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// The return value may be an array structure, not a string.
|
|
|
-
|
|
|
-// Each part has a different structure.
|
|
|
-
|
|
|
-print_r( $orderData );]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- </sect3>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <sect3 id="zend.db.select.other.reset">
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <title>Resetting Parts of the Select Object</title>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The <code>reset()</code> method enables you to clear one
|
|
|
-
|
|
|
- specified part of the SQL query, or else clear all parts of
|
|
|
-
|
|
|
- the SQL query if you omit the argument.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- The single argument is optional. You can specify the part
|
|
|
-
|
|
|
- of the query to clear, using the same strings you used in
|
|
|
-
|
|
|
- the argument to the <code>getPart()</code> method.
|
|
|
-
|
|
|
- The part of the query you specify is reset to a default state.
|
|
|
-
|
|
|
- </para>
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
- <para>
|
|
|
-
|
|
|
- If you omit the parameter, <code>reset()</code> changes all
|
|
|
-
|
|
|
- parts of the query to their default state. This makes the
|
|
|
-
|
|
|
- Zend_Db_Select object equivalent to a new object, as though you
|
|
|
-
|
|
|
- had just instantiated it.
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-
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|
|
- </para>
|
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-
|
|
|
-
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|
|
-
|
|
|
- <example id="zend.db.select.other.reset.example">
|
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|
-
|
|
|
- <title>Example of the reset() method</title>
|
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|
-
|
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|
- <programlisting role="php"><![CDATA[<?php
|
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-
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-
|
|
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-
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|
|
-// Build this query:
|
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|
-
|
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|
-// SELECT p.*
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|
-
|
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|
-// FROM "products" AS p
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|
-
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|
|
-// ORDER BY "product_name"
|
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|
-
|
|
|
-
|
|
|
-
|
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|
-$select = $db->select()
|
|
|
-
|
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|
- ->from(array('p' => 'products')
|
|
|
-
|
|
|
- ->order('product_name');
|
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|
-
|
|
|
-
|
|
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-
|
|
|
-// Changed requirement, instead order by a different columns:
|
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|
-
|
|
|
-// SELECT p.*
|
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|
-
|
|
|
-// FROM "products" AS p
|
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-
|
|
|
-// ORDER BY "product_id"
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Clear one part so we can redefine it
|
|
|
-
|
|
|
-$select->reset( Zend_Db_Select::ORDER );
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// And specify a different column
|
|
|
-
|
|
|
-$select->order('product_id');
|
|
|
-
|
|
|
-
|
|
|
-
|
|
|
-// Clear all parts of the query
|
|
|
-
|
|
|
-$select->reset();]]></programlisting>
|
|
|
-
|
|
|
- </example>
|
|
|
-
|
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|
-
|
|
|
-
|
|
|
- </sect3>
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-
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-
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-
|
|
|
- </sect2>
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-
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-
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|
-
|
|
|
-</sect1>
|
|
|
-
|
|
|
-<!--
|
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|
-
|
|
|
-vim:se ts=4 sw=4 et:
|
|
|
-
|
|
|
--->
|
|
|
-
|
|
|
+<sect1 id="zend.db.select">
|
|
|
+
|
|
|
+ <title>Zend_Db_Select</title>
|
|
|
+
|
|
|
+ <sect2 id="zend.db.select.introduction">
|
|
|
+
|
|
|
+ <title>Visão Geral do Objeto Select</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ O objeto Zend_Db_Select representa um comando de consulta SQL <code>SELECT</code>.
|
|
|
+ A classe possui métodos para a adição de partes individuais em uma query. Você
|
|
|
+ pode especificar algumas partes da consulta usando métodos PHP e estruturas de
|
|
|
+ dados, e a classe se encarrega de formar a sintaxe SQL correta para você. Depois
|
|
|
+ da construção de uma consulta, você pode executá-la como se você houvesse a escrito
|
|
|
+ em uma string.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ As vantagens oferecidas pelo Zend_Db_Select incluem:
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <itemizedlist>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ Métodos orientados a objetos para especificação de consultas SQL
|
|
|
+ de maneira "piece-by-piece" (aos pedaços ou em partes);
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ Abstração de independência de base de dados de algumas partes
|
|
|
+ da consulta SQL;
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ Colocação automática de aspas nos identificadores de metadados na maioria
|
|
|
+ dos casos, para dar suporte aos identificadores que contém palavras SQL reservadas
|
|
|
+ e caracteres especiais;
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ Colocação automática de aspas nos identificadores e valores, para ajudar
|
|
|
+ na redução de ataques por "SQL injection".
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ </itemizedlist>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ A utilização de Zend_Db_Select não é obrigatória. Para consultas SELECT
|
|
|
+ muito simples, normalmente é mais fácil escrever toda a consulta SQL
|
|
|
+ em uma string e executá-la usando métodos da classe Adapter, como o
|
|
|
+ <code>query()</code> ou <code>fetchAll()</code>. O uso de Zend_Db_Select
|
|
|
+ é muito útil quando você precisa montar uma consulta SELECT usando "procedures"
|
|
|
+ (através de procedimentos), ou quando você precisa montar a consulta baseando-se
|
|
|
+ na lógica condicional da sua aplicação.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ </sect2>
|
|
|
+
|
|
|
+ <sect2 id="zend.db.select.creating">
|
|
|
+
|
|
|
+ <title>Criando um Objeto Select</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Você pode criar uma instância de um objeto Zend_Db_Select
|
|
|
+ usando o método <code>select()</code> de um objeto Zend_Db_Adapter_Abstract.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.creating.example-db">
|
|
|
+ <title>Exemplo do método select() do adaptador para bases de dados</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$db = Zend_Db::factory( ...options... );
|
|
|
+$select = $db->select();]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Outra forma de criar um objeto Zend_Db_Select é com o
|
|
|
+ construtor dele, especificando o adaptador como parâmetro.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.creating.example-new">
|
|
|
+ <title>Examplo da criação de um novo objeto Select</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$db = Zend_Db::factory( ...options... );
|
|
|
+$select = new Zend_Db_Select($db);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect2>
|
|
|
+
|
|
|
+ <sect2 id="zend.db.select.building">
|
|
|
+
|
|
|
+ <title>Construindo Consultas Select</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Ao contruir um consulta, você pode adicionar cláusulas uma por uma.
|
|
|
+ Existe um método diferente para cada cláusula no objeto.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.example">
|
|
|
+ <title>Exemplo do uso de métodos para adicionar cláusulas</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Create the Zend_Db_Select object
|
|
|
+$select = $db->select();
|
|
|
+
|
|
|
+// Add a FROM clause
|
|
|
+$select->from( ...specify table and columns... )
|
|
|
+
|
|
|
+// Add a WHERE clause
|
|
|
+$select->where( ...specify search criteria... )
|
|
|
+
|
|
|
+// Add an ORDER BY clause
|
|
|
+$select->order( ...specify sorting criteria... );]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Você também pode usar a maior parte dos métodos do objeto Zend_Db_Select
|
|
|
+ com uma interface "fluent" conveniente. Uma interface "fluent" significa que cada
|
|
|
+ método retorna uma referência para o objeto no qual foi chamado, então você pode
|
|
|
+ imediatamente chamar outro método.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.example-fluent">
|
|
|
+ <title>Examplo de uso da interface "fluent"</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from( ...specify table and columns... )
|
|
|
+ ->where( ...specify search criteria... )
|
|
|
+ ->order( ...specify sorting criteria... );]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Os exemplos nesta seção mostram o uso da interface "fluent",
|
|
|
+ mas você pode usar a interface "non-fluent" em todos os casos.
|
|
|
+ É freqüentemente necessário usar a interface "non-fluent" quando, por exemplo,
|
|
|
+ sua aplicação precisa executar alguma lógica antes de adicionar uma cláusula
|
|
|
+ a uma consulta.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.from">
|
|
|
+
|
|
|
+ <title>Adicionando uma cláusula FROM</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Especifique a tabela para esta consulta usando o método <code>from()</code>.
|
|
|
+ Você pode especificar o nome da tabela como uma simples string.
|
|
|
+ Zend_Db_Select coloca o entre aspas o nome da tabela, então, você pode
|
|
|
+ usar caracteres especiais.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.from.example">
|
|
|
+ <title>Example of the from() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT *
|
|
|
+// FROM "products"
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from( 'products' );]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ You can also specify the correlation name (sometimes called the
|
|
|
+ "table alias") for a table. Instead of a simple string, use an
|
|
|
+ associative array mapping the correlation name to the table
|
|
|
+ name. In other clauses of the SQL query, use this correlation
|
|
|
+ name. If your query joins more than one table, Zend_Db_Select
|
|
|
+ generates unique correlation names based on the table names,
|
|
|
+ for any tables for which you don't specify the correlation name.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.from.example-cname">
|
|
|
+ <title>Example of specifying a table correlation name</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p.*
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from( array('p' => 'products') );]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Algumas marcas de RDBMS dão suporte a um especificador de schema
|
|
|
+ para uma tabela. Você pode especificar o nome a tabela como
|
|
|
+ "<code>schemaName.tableName</code>", onde Zend_Db_Select coloca entre aspas
|
|
|
+ cada uma das partes individualmente, ou então você deve especificar o nome
|
|
|
+ do schema separadamente. Um nome de schema especificado no nome da tabela
|
|
|
+ precede um schema fornecido separadamente se eventualmente ambos forem
|
|
|
+ informados.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.from.example-schema">
|
|
|
+ <title>Exemplo de especificação de nome de schema</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT *
|
|
|
+// FROM "myschema"."products"
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from( 'myschema.products' );
|
|
|
+
|
|
|
+// or
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products', '*', 'myschema');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.columns">
|
|
|
+
|
|
|
+ <title>Adicionando Colunas</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ No segundo argumento do método <code>from()</code> ,
|
|
|
+ você pode especificaras colunas a serem selecionadas da
|
|
|
+ respectiva tabela. Se você não especificar nenhuma coluna,
|
|
|
+ o valor padrão é "<code>*</code>", o caracter curinga para "todas as colunas".
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Você pode listar as colunas em um simples array de strings, ou como
|
|
|
+ um mapeamento associativo do alias da coluna para nome da coluna.
|
|
|
+ Se você só tiver uma coluna para consultar, e não precisar indicar um
|
|
|
+ alias, você pode listá-la em uma string simples ao invés de um array.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Se você passar um array vazio como o argumento de colunas, nenhuma
|
|
|
+ coluna da respectiva tabela será incluída no result set.
|
|
|
+ Veja um exemplo de <link linkend="zend.db.select.building.join.example-no-columns">código</link> sob a seção do método <code>join()</code>.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Você pode especificar o nome da coluna como
|
|
|
+ "<code>correlationName.columnName</code>".
|
|
|
+ Zend_Db_Select os coloca entre aspas individualmente.
|
|
|
+ Caso você não especifique o nome da correlação para uma coluna,
|
|
|
+ é usado o nome da correlação da tabela indicada no método<code>from()</code>.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.columns.example">
|
|
|
+ <title>Examples of specifying columns</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'product_name'));
|
|
|
+
|
|
|
+// Build the same query, specifying correlation names:
|
|
|
+// SELECT p."product_id", p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('p.product_id', 'p.product_name'));
|
|
|
+
|
|
|
+// Build this query with an alias for one column:
|
|
|
+// SELECT p."product_id" AS prodno, p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('prodno' => 'product_id', 'product_name'));]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.columns-expr">
|
|
|
+
|
|
|
+ <title>Adicionando Colunas de Expressões</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Algumas vezes as colunas de uma consulta SQL são expressões, e não
|
|
|
+ simplesmente o nome de uma couna da tabela. Expressões não devem usar
|
|
|
+ nomes de correlação ou aspas. Se a string da coluna possuir parênteses,
|
|
|
+ Zend_Db_Select a reconhecerá como uma expressão.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Você também pode criar um objeto do tipo Zend_Db_Expr explicitamente,
|
|
|
+ para prevenir que uma string seja tratada como um nome de coluna.
|
|
|
+ Zend_Db_Expr é uma classe diminuta que contém uma única string.
|
|
|
+ Zend_Db_Select reconhece obtejos do tipo Zend_Db_Expr e os converte
|
|
|
+ novamente para strings, mas não efetua qualquer alteração como a
|
|
|
+ colocação de aspas ou nomes de correlação.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <note>
|
|
|
+ <para>
|
|
|
+ O uso de Zend_Db_Expr para nomes de colunas não é necessário se as
|
|
|
+ expressões contiverem parênteses; Zend_Db_Select reconhece os parênteses
|
|
|
+ e trata a string como uma expresão, ignorando a colocação de aspas e de
|
|
|
+ nomes de correlação.
|
|
|
+ </para>
|
|
|
+ </note>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.columns-expr.example">
|
|
|
+ <title>Exemplos de especificação de colunas contendo expressões</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", LOWER(product_name)
|
|
|
+// FROM "products" AS p
|
|
|
+// An expression with parentheses implicitly becomes
|
|
|
+// a Zend_Db_Expr.
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'LOWER(product_name)'));
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", (p.cost * 1.08) AS cost_plus_tax
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'cost_plus_tax' => '(p.cost * 1.08)'));
|
|
|
+
|
|
|
+// Build this query using Zend_Db_Expr explicitly:
|
|
|
+// SELECT p."product_id", p.cost * 1.08 AS cost_plus_tax
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'cost_plus_tax' => new Zend_Db_Expr('p.cost * 1.08')));]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Nos casos acima, Zend_Db_Select não altera a string
|
|
|
+ para colocar os nomes de correlação ou aspas. Se as
|
|
|
+ mudanças forem necessárias para evitar alguma ambiguidade,
|
|
|
+ você deve fazê-las manualmente na string.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Se os nomes das colunas são palavras-chave SQL ou possuem
|
|
|
+ caracteres especiais, você deve usar o método <code>quoteIdentifier()</code>
|
|
|
+ da classe Adapter, e interpolar o resultado na string. O método
|
|
|
+ <code>quoteIdentifier()</code> usa aspas no SQL para delimitar o identificador,
|
|
|
+ o que deixa claro que ele é um identificador de uma tabela ou coluna e não
|
|
|
+ parte da síntaxe SQL.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Seu código fica mais independente de base de dados se você
|
|
|
+ usar o método <code>quoteIdentifier()</code> ao invés de digitar
|
|
|
+ as aspas nas strings porque algumas marcas de SGBD Relacionais usam
|
|
|
+ símbolos fora do padrão para referenciar identificadores.
|
|
|
+ O método <code>quoteIdentifier()</code> é projetado para usar
|
|
|
+ os símbolos de referência apropriados de acordo com o tipo de adaptador.
|
|
|
+ O método <code>quoteIdentifier()</code> também ignora qualquer
|
|
|
+ caracter de referência que aparecer no nome de um identificador.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.columns-quoteid.example">
|
|
|
+ <title>Examples of quoting columns in an expression</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query, quoting a special column name "from" in the expression:
|
|
|
+// SELECT p."from" + 10 AS origin
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('origin' => '(p.' . $db->quoteIdentifier('from') . ' + 10)'));]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.join">
|
|
|
+
|
|
|
+ <title>Adding Another Table to the Query with JOIN</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Many useful queries involve using a <code>JOIN</code>
|
|
|
+ to combine rows from multiple tables. You can add
|
|
|
+ tables to a Zend_Db_Select query using the
|
|
|
+ <code>join()</code> method. Using this method is
|
|
|
+ similar to the <code>from()</code> method, except
|
|
|
+ you can also specify a join condition in most cases.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.join.example">
|
|
|
+ <title>Example of the join() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", p."product_name", l.*
|
|
|
+// FROM "products" AS p JOIN "line_items" AS l
|
|
|
+// ON p.product_id = l.product_id
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'product_name'))
|
|
|
+ ->join(array('l' => 'line_items'),
|
|
|
+ 'p.product_id = l.product_id');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The second argument to <code>join()</code> is a string
|
|
|
+ that is the join condition. This is an expression that
|
|
|
+ declares the criteria by which rows in one table match
|
|
|
+ rows in the the other table. You can use correlation
|
|
|
+ names in this expression.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <note>
|
|
|
+ <para>
|
|
|
+ No quoting is applied to the expression you specify
|
|
|
+ for the join condition; if you have column names that need
|
|
|
+ to be quoted, you must use <code>quoteIdentifier()</code>
|
|
|
+ as you form the string for the join condition.
|
|
|
+ </para>
|
|
|
+ </note>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The third argument to <code>join()</code> is an array
|
|
|
+ of column names, like that used in the <code>from()</code>
|
|
|
+ method. It defaults to "<code>*</code>", supports correlation
|
|
|
+ names, expressions, and Zend_Db_Expr in the same way as the
|
|
|
+ array of column names in the <code>from()</code> method.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ To select no columns from a table, use an empty array for
|
|
|
+ the list of columns. This usage works in the
|
|
|
+ <code>from()</code> method too, but typically you want
|
|
|
+ some columns from the primary table in your queries,
|
|
|
+ whereas you might want no columns from a joined table.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.join.example-no-columns">
|
|
|
+ <title>Example of specifying no columns</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", p."product_name"
|
|
|
+// FROM "products" AS p JOIN "line_items" AS l
|
|
|
+// ON p.product_id = l.product_id
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id', 'product_name'))
|
|
|
+ ->join(array('l' => 'line_items'),
|
|
|
+ 'p.product_id = l.product_id',
|
|
|
+ array() ); // empty list of columns]]></programlisting>
|
|
|
+ <para>
|
|
|
+ Note the empty <code>array()</code> in the above example
|
|
|
+ in place of a list of columns from the joined table.
|
|
|
+ </para>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ SQL has several types of joins.
|
|
|
+ See the list below for the methods to support
|
|
|
+ different join types in Zend_Db_Select.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <itemizedlist>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>INNER JOIN</command> with the
|
|
|
+ <code>join(table, join, [columns])</code>
|
|
|
+ or <code>joinInner(table, join, [columns])</code> methods.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ This may be the most common type of join. Rows from
|
|
|
+ each table are compared using the join condition you
|
|
|
+ specify. The result set includes only the rows that
|
|
|
+ satisfy the join condition. The result set can be
|
|
|
+ empty if no rows satisfy this condition.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ All RDBMS brands support this join type.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>LEFT JOIN</command> with the
|
|
|
+ <code>joinLeft(table, condition, [columns])</code> method.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ All rows from the left operand table are included,
|
|
|
+ matching rows from the right operand table included,
|
|
|
+ and the columns from the right operand table are filled
|
|
|
+ with NULLs if no row exists matching the left table.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ All RDBMS brands support this join type.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>RIGHT JOIN</command> with the
|
|
|
+ <code>joinRight(table, condition, [columns])</code> method.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ Right outer join is the complement of left outer join.
|
|
|
+ All rows from the right operand table are included,
|
|
|
+ matching rows from the left operand table included,
|
|
|
+ and the columns from the left operand table are filled
|
|
|
+ with NULLs if no row exists matching the right table.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ Some RDBMS brands don't support this join type, but
|
|
|
+ in general any right join can be represented as a left
|
|
|
+ join by reversing the order of the tables.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>FULL JOIN</command> with the
|
|
|
+ <code>joinFull(table, condition, [columns])</code> method.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ A full outer join is like combining a left outer join
|
|
|
+ and a right outer join. All rows from both tables are
|
|
|
+ included, paired with each other on the same row of the
|
|
|
+ result set if they satisfy the join condition, and
|
|
|
+ otherwise paired with NULLs in place of columns from the
|
|
|
+ other table.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ Some RDBMS brands don't support this join type.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>CROSS JOIN</command> with the
|
|
|
+ <code>joinCross(table, [columns])</code> method.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ A cross join is a Cartesian product.
|
|
|
+ Every row in the first table is matched to every
|
|
|
+ row in the second table. Therefore the number of
|
|
|
+ rows in the result set is equal to the product of
|
|
|
+ the number of rows in each table. You can filter
|
|
|
+ the result set using conditions in a WHERE clause;
|
|
|
+ in this way a cross join is similar to the old SQL-89
|
|
|
+ join syntax.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ The <code>joinCross()</code> method has no parameter
|
|
|
+ to specify the join condition.
|
|
|
+ Some RDBMS brands don't support this join type.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ <listitem>
|
|
|
+ <para>
|
|
|
+ <command>NATURAL JOIN</command> with the
|
|
|
+ <code>joinNatural(table, [columns])</code> method.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ A natural join compares any column(s) that appear with
|
|
|
+ the same name in both tables. The comparison is
|
|
|
+ equality of all the column(s); comparing the columns
|
|
|
+ using inequality is not a natural join.
|
|
|
+ Only natural inner joins are supported by this API,
|
|
|
+ even though SQL permits natural outer joins as well.
|
|
|
+ </para>
|
|
|
+ <para>
|
|
|
+ The <code>joinNatural()</code> method has no parameter
|
|
|
+ to specify the join condition.
|
|
|
+ </para>
|
|
|
+ </listitem>
|
|
|
+ </itemizedlist>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.where">
|
|
|
+
|
|
|
+ <title>Adding a WHERE Clause</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ You can specify criteria for restricting rows of the result set
|
|
|
+ using the <code>where()</code> method. The first argument of
|
|
|
+ this method is a SQL expression, and this expression is used
|
|
|
+ in a SQL <code>WHERE</code> clause in the query.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.where.example">
|
|
|
+ <title>Example of the where() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT product_id, product_name, price
|
|
|
+// FROM "products"
|
|
|
+// WHERE price > 100.00
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(
|
|
|
+ 'products',
|
|
|
+ array('product_id', 'product_name', 'price'))
|
|
|
+ ->where('price > 100.00');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <note>
|
|
|
+ <para>
|
|
|
+ No quoting is applied to expressions given to the
|
|
|
+ <code>where()</code> or <code>orWhere()</code> methods.
|
|
|
+ If you have column names that need to be quoted, you must use
|
|
|
+ <code>quoteIdentifier()</code> as you form the string for the
|
|
|
+ condition.
|
|
|
+ </para>
|
|
|
+ </note>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The second argument to the <code>where()</code> method is
|
|
|
+ optional. It is a value to substitute into the expression.
|
|
|
+ Zend_Db_Select quotes the value and substitutes it for a
|
|
|
+ question-mark ("<code>?</code>") symbol in the expression.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ This method accepts only one parameter.
|
|
|
+ If you have an expression into which you need to substitute
|
|
|
+ multiple variables, you must format the string manually,
|
|
|
+ interpolating variables and performing quoting yourself.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.where.example-param">
|
|
|
+ <title>Example of a parameter in the where() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT product_id, product_name, price
|
|
|
+// FROM "products"
|
|
|
+// WHERE (price > 100.00)
|
|
|
+
|
|
|
+$minimumPrice = 100;
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(
|
|
|
+ 'products',
|
|
|
+ array('product_id', 'product_name', 'price'))
|
|
|
+ ->where('price > ?', $minimumPrice);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ You can invoke the <code>where()</code> method multiple times
|
|
|
+ on the same Zend_Db_Select object. The resulting query combines
|
|
|
+ the multiple terms together using <code>AND</code> between them.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.where.example-and">
|
|
|
+ <title>Example of multiple where() methods</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT product_id, product_name, price
|
|
|
+// FROM "products"
|
|
|
+// WHERE (price > 100.00)
|
|
|
+// AND (price < 500.00)
|
|
|
+
|
|
|
+$minimumPrice = 100;
|
|
|
+$maximumPrice = 500;
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products',
|
|
|
+ array('product_id', 'product_name', 'price'))
|
|
|
+ ->where('price > ?', $minimumPrice)
|
|
|
+ ->where('price < ?', $maximumPrice);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ If you need to combine terms together using <code>OR</code>,
|
|
|
+ use the <code>orWhere()</code> method. This method is used
|
|
|
+ in the same way as the <code>where()</code> method, except
|
|
|
+ that the term specified is preceded by <code>OR</code>,
|
|
|
+ instead of <code>AND</code>.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.where.example-or">
|
|
|
+ <title>Example of the orWhere() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT product_id, product_name, price
|
|
|
+// FROM "products"
|
|
|
+// WHERE (price < 100.00)
|
|
|
+// OR (price > 500.00)
|
|
|
+
|
|
|
+$minimumPrice = 100;
|
|
|
+$maximumPrice = 500;
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products',
|
|
|
+ array('product_id', 'product_name', 'price'))
|
|
|
+ ->where('price < ?', $minimumPrice)
|
|
|
+ ->orWhere('price > ?', $maximumPrice);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Zend_Db_Select automatically puts parentheses around each
|
|
|
+ expression you specify using the <code>where()</code> or
|
|
|
+ <code>orWhere()</code> methods. This helps to ensure that
|
|
|
+ Boolean operator precedence does not cause unexpected
|
|
|
+ results.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.where.example-parens">
|
|
|
+ <title>Example of parenthesizing Boolean expressions</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT product_id, product_name, price
|
|
|
+// FROM "products"
|
|
|
+// WHERE (price < 100.00 OR price > 500.00)
|
|
|
+// AND (product_name = 'Apple')
|
|
|
+
|
|
|
+$minimumPrice = 100;
|
|
|
+$maximumPrice = 500;
|
|
|
+$prod = 'Apple';
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products',
|
|
|
+ array('product_id', 'product_name', 'price'))
|
|
|
+ ->where("price < $minimumPrice OR price > $maximumPrice")
|
|
|
+ ->where('product_name = ?', $prod);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In the example above, the results would be quite different
|
|
|
+ without the parentheses, because <code>AND</code> has higher
|
|
|
+ precedence than <code>OR</code>. Zend_Db_Select applies the
|
|
|
+ parentheses so the effect is that each expression in successive
|
|
|
+ calls to the <code>where()</code> bind more tightly than the
|
|
|
+ <code>AND</code> that combines the expressions.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.group">
|
|
|
+
|
|
|
+ <title>Adding a GROUP BY Clause</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In SQL, the <code>GROUP BY</code> clause allows you
|
|
|
+ to reduce the rows of a query result set to one row per
|
|
|
+ unique value found in the column(s) named in the
|
|
|
+ <code>GROUP BY</code> clause.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In Zend_Db_Select, you can specify the column(s) to use
|
|
|
+ for calculating the groups of rows using the
|
|
|
+ <code>group()</code> method. The argument to this
|
|
|
+ method is a column or an array of columns to use in
|
|
|
+ the <code>GROUP BY</code> clause.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.group.example">
|
|
|
+ <title>Example of the group() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
+// FROM "products" AS p JOIN "line_items" AS l
|
|
|
+// ON p.product_id = l.product_id
|
|
|
+// GROUP BY p.product_id
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id'))
|
|
|
+ ->join(array('l' => 'line_items'),
|
|
|
+ 'p.product_id = l.product_id',
|
|
|
+ array('line_items_per_product' => 'COUNT(*)'))
|
|
|
+ ->group('p.product_id');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Like the columns array in the <code>from()</code> method, you
|
|
|
+ can use correlation names in the column name strings, and the
|
|
|
+ column is quoted as an identifier unless the string contains
|
|
|
+ parentheses or is an object of type Zend_Db_Expr.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.having">
|
|
|
+
|
|
|
+ <title>Adding a HAVING Clause</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In SQL, the <code>HAVING</code> clause applies a restriction
|
|
|
+ condition on groups of rows. This is similar to how a
|
|
|
+ <code>WHERE</code> clause applies a restriction condition on rows.
|
|
|
+ But the two clauses are different because <code>WHERE</code>
|
|
|
+ conditions are applied before groups are defined, whereas
|
|
|
+ <code>HAVING</code> conditions are applied after groups are
|
|
|
+ defined.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In Zend_Db_Select, you can specify conditions for restricting
|
|
|
+ groups using the <code>having()</code> method. Its usage is
|
|
|
+ similar to that of the <code>where()</code> method.
|
|
|
+ The first argument is a string containing a SQL expression.
|
|
|
+ The optional second argument is a value that is used to replace
|
|
|
+ a positional parameter placeholder in the SQL expression.
|
|
|
+ Expressions given in multiple invocations of the
|
|
|
+ <code>having()</code> method are combined using the Boolean
|
|
|
+ <code>AND</code> operator, or the <code>OR</code> operator if
|
|
|
+ you use the <code>orHaving()</code> method.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.having.example">
|
|
|
+ <title>Example of the having() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
+// FROM "products" AS p JOIN "line_items" AS l
|
|
|
+// ON p.product_id = l.product_id
|
|
|
+// GROUP BY p.product_id
|
|
|
+// HAVING line_items_per_product > 10
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id'))
|
|
|
+ ->join(array('l' => 'line_items'),
|
|
|
+ 'p.product_id = l.product_id',
|
|
|
+ array('line_items_per_product' => 'COUNT(*)'))
|
|
|
+ ->group('p.product_id')
|
|
|
+ ->having('line_items_per_product > 10');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <note>
|
|
|
+ <para>
|
|
|
+ No quoting is applied to expressions given to the
|
|
|
+ <code>having()</code> or <code>orHaving()</code> methods.
|
|
|
+ If you have column names that need to be quoted, you must use
|
|
|
+ <code>quoteIdentifier()</code> as you form the string for the
|
|
|
+ condition.
|
|
|
+ </para>
|
|
|
+ </note>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.order">
|
|
|
+
|
|
|
+ <title>Adding an ORDER BY Clause</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In SQL, the <code>ORDER BY</code> clause specifies one or more
|
|
|
+ columns or expressions by which the result set of a query is
|
|
|
+ sorted. If multiple columns are listed, the secondary columns
|
|
|
+ are used to resolve ties; the sort order is determined by the
|
|
|
+ secondary columns if the preceding columns contain identical
|
|
|
+ values. The default sorting is from least value to greatest
|
|
|
+ value. You can also sort by greatest value to least value for
|
|
|
+ a given column in the list by specifying the keyword
|
|
|
+ <code>DESC</code> after that column.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In Zend_Db_Select, you can use the <code>order()</code> method
|
|
|
+ to specify a column or an array of columns by which to sort.
|
|
|
+ Each element of the array is a string naming a column.
|
|
|
+ optionally with the <code>ASC</code> <code>DESC</code> keyword
|
|
|
+ following it, separated by a space.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Like in the <code>from()</code> and <code>group()</code>
|
|
|
+ methods, column names are quoted as identifiers, unless they
|
|
|
+ contain contain parentheses or are an object of type
|
|
|
+ Zend_Db_Expr.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.order.example">
|
|
|
+ <title>Example of the order() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", COUNT(*) AS line_items_per_product
|
|
|
+// FROM "products" AS p JOIN "line_items" AS l
|
|
|
+// ON p.product_id = l.product_id
|
|
|
+// GROUP BY p.product_id
|
|
|
+// ORDER BY "line_items_per_product" DESC, "product_id"
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'),
|
|
|
+ array('product_id'))
|
|
|
+ ->join(array('l' => 'line_items'),
|
|
|
+ 'p.product_id = l.product_id',
|
|
|
+ array('line_items_per_product' => 'COUNT(*)'))
|
|
|
+ ->group('p.product_id')
|
|
|
+ ->order(array('line_items_per_product DESC', 'product_id'));]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.limit">
|
|
|
+
|
|
|
+ <title>Adding a LIMIT Clause</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Some RDBMS brands extend SQL with a query clause known as the
|
|
|
+ <code>LIMIT</code> clause. This clause reduces the number of
|
|
|
+ rows in the result set to at most a number you specify.
|
|
|
+ You can also specify to skip a number of rows before starting
|
|
|
+ to output.
|
|
|
+ This feature makes it easy to take a subset of a result set,
|
|
|
+ for example when displaying query results on progressive pages
|
|
|
+ of output.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ In Zend_Db_Select, you can use the <code>limit()</code> method
|
|
|
+ to specify the count of rows and the number of rows to skip.
|
|
|
+ The first argument to this method is the desired count of rows.
|
|
|
+ The second argument is the number of rows to skip.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.limit.example">
|
|
|
+ <title>Example of the limit() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+// LIMIT 10, 20
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'), array('product_id', 'product_name'))
|
|
|
+ ->limit(10, 20);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ <note>
|
|
|
+ <para>
|
|
|
+ The <code>LIMIT</code> syntax is not supported by all RDBMS
|
|
|
+ brands. Some RDBMS require different syntax to support
|
|
|
+ similar functionality. Each Zend_Db_Adapter_Abstract class
|
|
|
+ includes a method to produce SQL appropriate for that RDBMS.
|
|
|
+ </para>
|
|
|
+ </note>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ Use the <code>limitPage()</code> method for an alternative way
|
|
|
+ to specify row count and offset. This method allows you to
|
|
|
+ limit the result set to one of a series of fixed-length subsets
|
|
|
+ of rows from the query's total result set. In other words, you
|
|
|
+ specify the length of a "page" of results, and the ordinal
|
|
|
+ number of the single page of results you want the query to return.
|
|
|
+ The page number is the first argument of the
|
|
|
+ <code>limitPage()</code> method, and the page length is the
|
|
|
+ second argument. Both arguments are required; they have no
|
|
|
+ default values.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.limit.example2">
|
|
|
+ <title>Example of the limitPage() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p."product_id", p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+// LIMIT 10, 20
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products'), array('product_id', 'product_name'))
|
|
|
+ ->limitPage(2, 10);]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.distinct">
|
|
|
+
|
|
|
+ <title>Adding the DISTINCT Query Modifier</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The <code>distinct()</code> method enables you to add the
|
|
|
+ <code>DISTINCT</code> keyword to your SQL query.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.distinct.example">
|
|
|
+ <title>Example of the distinct() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT DISTINCT p."product_name"
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->distinct()
|
|
|
+ ->from(array('p' => 'products'), 'product_name');]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.building.for-update">
|
|
|
+
|
|
|
+ <title>Adding the FOR UPDATE Query Modifier</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The <code>forUpdate()</code> method enables you to add the
|
|
|
+ <code>FOR UPDATE</code> modifier to your SQL query.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.building.for-update.example">
|
|
|
+ <title>Example of forUpdate() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT FOR UPDATE p.*
|
|
|
+// FROM "products" AS p
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->forUpdate()
|
|
|
+ ->from(array('p' => 'products'));]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ </sect2>
|
|
|
+
|
|
|
+ <sect2 id="zend.db.select.execute">
|
|
|
+
|
|
|
+ <title>Executing Select Queries</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ This section describes how to execute the query represented by a
|
|
|
+ Zend_Db_Select object.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.execute.query-adapter">
|
|
|
+
|
|
|
+ <title>Executing Select Queries from the Db Adapter</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ You can execute the query represented by the Zend_Db_Select
|
|
|
+ object by passing it as the first argument to the
|
|
|
+ <code>query()</code> method of a Zend_Db_Adapter_Abstract
|
|
|
+ object. Use the Zend_Db_Select objects instead of a string
|
|
|
+ query.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The <code>query()</code> method returns an object of type
|
|
|
+ Zend_Db_Statement or PDOStatement, depending on the adapter type.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.execute.query-adapter.example">
|
|
|
+ <title>Example using the Db adapter's query() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products');
|
|
|
+
|
|
|
+$stmt = $db->query($select);
|
|
|
+$result = $stmt->fetchAll();]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.execute.query-select">
|
|
|
+
|
|
|
+ <title>Executing Select Queries from the Object</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ As an alternative to using the <code>query()</code> method
|
|
|
+ of the adapter object, you can use the <code>query()</code>
|
|
|
+ method of the Zend_Db_Select object.
|
|
|
+ Both methods return an object of type Zend_Db_Statement or
|
|
|
+ PDOStatement, depending on the adapter type.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.execute.query-select.example">
|
|
|
+ <title>Example using the Select object's query method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products');
|
|
|
+
|
|
|
+$stmt = $select->query();
|
|
|
+$result = $stmt->fetchAll();]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.execute.tostring">
|
|
|
+
|
|
|
+ <title>Converting a Select Object to a SQL String</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ If you need access to a string representation of the SQL
|
|
|
+ query corresponding to the Zend_Db_Select object, use
|
|
|
+ the <code>__toString()</code> method.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.execute.tostring.example">
|
|
|
+ <title>Example of the __toString() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products');
|
|
|
+
|
|
|
+$sql = $select->__toString();
|
|
|
+echo "$sql\n";
|
|
|
+
|
|
|
+// The output is the string:
|
|
|
+// SELECT * FROM "products"]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ </sect2>
|
|
|
+
|
|
|
+ <sect2 id="zend.db.select.other">
|
|
|
+
|
|
|
+ <title>Other methods</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ This section describes other methods of the Zend_Db_Select class
|
|
|
+ that are not covered above: <code>getPart()</code> and
|
|
|
+ <code>reset()</code>.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.other.get-part">
|
|
|
+
|
|
|
+ <title>Retrieving Parts of the Select Object</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The <code>getPart()</code> method returns a representation
|
|
|
+ of one part of your SQL query. For example, you can use this
|
|
|
+ method to return the array of expressions for the
|
|
|
+ <code>WHERE</code> clause, or the array of columns
|
|
|
+ (or column expressions) that are in the <code>SELECT</code>
|
|
|
+ list, or the values of the count and offset for the
|
|
|
+ <code>LIMIT</code> clause.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The return value is not a string containing a fragment of SQL
|
|
|
+ syntax. The return value is an internal representation, which
|
|
|
+ is typically an array structure containing values and
|
|
|
+ expressions. Each part of the query has a different structure.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The single argument to the <code>getPart()</code> method is
|
|
|
+ a string that identifies which part of the Select query to
|
|
|
+ return. For example, the string <code>'from'</code>
|
|
|
+ identifies the part of the Select object that stores
|
|
|
+ information about the tables in the <code>FROM</code> clause,
|
|
|
+ including joined tables.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The Zend_Db_Select class defines constants you can use for
|
|
|
+ parts of the SQL query. You can use these constant definitions,
|
|
|
+ or you can the literal strings.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <table id="zend.db.select.other.get-part.table">
|
|
|
+ <title>Constants used by getPart() and reset()</title>
|
|
|
+ <tgroup cols="2">
|
|
|
+ <thead>
|
|
|
+ <row>
|
|
|
+ <entry>Constant</entry>
|
|
|
+ <entry>String value</entry>
|
|
|
+ </row>
|
|
|
+ </thead>
|
|
|
+ <tbody>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::DISTINCT</code></entry>
|
|
|
+ <entry><code>'distinct'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::FOR_UPDATE</code></entry>
|
|
|
+ <entry><code>'forupdate'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::COLUMNS</code></entry>
|
|
|
+ <entry><code>'columns'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::FROM</code></entry>
|
|
|
+ <entry><code>'from'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::WHERE</code></entry>
|
|
|
+ <entry><code>'where'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::GROUP</code></entry>
|
|
|
+ <entry><code>'group'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::HAVING</code></entry>
|
|
|
+ <entry><code>'having'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::ORDER</code></entry>
|
|
|
+ <entry><code>'order'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::LIMIT_COUNT</code></entry>
|
|
|
+ <entry><code>'limitcount'</code></entry>
|
|
|
+ </row>
|
|
|
+ <row>
|
|
|
+ <entry><code>Zend_Db_Select::LIMIT_OFFSET</code></entry>
|
|
|
+ <entry><code>'limitoffset'</code></entry>
|
|
|
+ </row>
|
|
|
+ </tbody>
|
|
|
+ </tgroup>
|
|
|
+ </table>
|
|
|
+
|
|
|
+ <example id="zend.db.select.other.get-part.example">
|
|
|
+ <title>Example of the getPart() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from('products')
|
|
|
+ ->order('product_id');
|
|
|
+
|
|
|
+// You can use a string literal to specify the part
|
|
|
+$orderData = $select->getPart( 'order' );
|
|
|
+
|
|
|
+// You can use a constant to specify the same part
|
|
|
+$orderData = $select->getPart( Zend_Db_Select::ORDER );
|
|
|
+
|
|
|
+// The return value may be an array structure, not a string.
|
|
|
+// Each part has a different structure.
|
|
|
+print_r( $orderData );]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ <sect3 id="zend.db.select.other.reset">
|
|
|
+
|
|
|
+ <title>Resetting Parts of the Select Object</title>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The <code>reset()</code> method enables you to clear one
|
|
|
+ specified part of the SQL query, or else clear all parts of
|
|
|
+ the SQL query if you omit the argument.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ The single argument is optional. You can specify the part
|
|
|
+ of the query to clear, using the same strings you used in
|
|
|
+ the argument to the <code>getPart()</code> method.
|
|
|
+ The part of the query you specify is reset to a default state.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <para>
|
|
|
+ If you omit the parameter, <code>reset()</code> changes all
|
|
|
+ parts of the query to their default state. This makes the
|
|
|
+ Zend_Db_Select object equivalent to a new object, as though you
|
|
|
+ had just instantiated it.
|
|
|
+ </para>
|
|
|
+
|
|
|
+ <example id="zend.db.select.other.reset.example">
|
|
|
+ <title>Example of the reset() method</title>
|
|
|
+ <programlisting role="php"><![CDATA[<?php
|
|
|
+
|
|
|
+// Build this query:
|
|
|
+// SELECT p.*
|
|
|
+// FROM "products" AS p
|
|
|
+// ORDER BY "product_name"
|
|
|
+
|
|
|
+$select = $db->select()
|
|
|
+ ->from(array('p' => 'products')
|
|
|
+ ->order('product_name');
|
|
|
+
|
|
|
+// Changed requirement, instead order by a different columns:
|
|
|
+// SELECT p.*
|
|
|
+// FROM "products" AS p
|
|
|
+// ORDER BY "product_id"
|
|
|
+
|
|
|
+// Clear one part so we can redefine it
|
|
|
+$select->reset( Zend_Db_Select::ORDER );
|
|
|
+
|
|
|
+// And specify a different column
|
|
|
+$select->order('product_id');
|
|
|
+
|
|
|
+// Clear all parts of the query
|
|
|
+$select->reset();]]></programlisting>
|
|
|
+ </example>
|
|
|
+
|
|
|
+ </sect3>
|
|
|
+
|
|
|
+ </sect2>
|
|
|
+
|
|
|
+</sect1>
|
|
|
+<!--
|
|
|
+vim:se ts=4 sw=4 et:
|
|
|
+-->
|
mauriciofauth