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fetchcolumn.xml
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fetchcolumn.xml
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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- EN-Revision: 28529d3539b850e870e3aa97570f4db0e53daa03 Maintainer: anonymous #27375 Status: ready -->
<!-- CREDITS: mowangjuanzi -->
<refentry xml:id="pdostatement.fetchcolumn" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>PDOStatement::fetchColumn</refname>
<refpurpose>
从结果集中的下一行返回单独的一列
</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis role="PDOStatement">
<modifier>public</modifier> <type>mixed</type><methodname>PDOStatement::fetchColumn</methodname>
<methodparam choice="opt"><type>int</type><parameter>column</parameter><initializer>0</initializer></methodparam>
</methodsynopsis>
<para>
从结果集中的下一行返回单独的一列,如果没有了,则返回 &false; 。
</para>
<note>
<para>
<methodname>PDOStatement::fetchColumn</methodname> 不应该用于检索 boolean 列,因为无法区分 &false;
值和没有更多行可检索。请改用 <methodname>PDOStatement::fetch</methodname>。
</para>
</note>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>column</parameter></term>
<listitem>
<para>
你想从行里取回的列的索引数字(以0开始的索引)。如果没有提供值,则 <methodname>PDOStatement::fetchColumn</methodname> 获取第一列。
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
<methodname>PDOStatement::fetchColumn</methodname> 从结果集中的下一行返回单独的一列,如果没有更多行,则返回 &false;。
</para>
<warning>
<para>
如果使用 <methodname>PDOStatement::fetchColumn</methodname> 取回数据,则没有办法返回同一行的另外一列。
</para>
</warning>
</refsect1>
<refsect1 role="errors">
&reftitle.errors;
&pdo.errors;
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example><title>返回下一行的第一列</title>
<programlisting role="php">
<![CDATA[
<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
print "Fetch the first column from the first row in the result set:\n";
$result = $sth->fetchColumn();
print "name = $result\n";
print "Fetch the second column from the second row in the result set:\n";
$result = $sth->fetchColumn(1);
print "colour = $result\n";
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
Fetch the first column from the first row in the result set:
name = lemon
Fetch the second column from the second row in the result set:
colour = red
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><methodname>PDO::query</methodname></member>
<member><methodname>PDOStatement::fetch</methodname></member>
<member><methodname>PDOStatement::fetchAll</methodname></member>
<member><methodname>PDO::prepare</methodname></member>
<member><methodname>PDOStatement::setFetchMode</methodname></member>
</simplelist>
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->