php-doc-en/reference/mysql/functions/mysql-data-seek.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.17 $ -->
<refentry id="function.mysql-data-seek">
 <refnamediv>
  <refname>mysql_data_seek</refname>
  <refpurpose>Move internal result pointer</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>mysql_data_seek</methodname>
   <methodparam><type>resource</type><parameter>result</parameter></methodparam>
   <methodparam><type>int</type><parameter>row_number</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>mysql_data_seek</function> moves the internal row
   pointer of the MySQL result associated with the specified result
   identifier to point to the specified row number.  The next call
   to <function>mysql_fetch_row</function> would return that row.
  </para>
  <para>
   <parameter>row_number</parameter> starts at 0. The 
   <parameter>row_number</parameter> should be a value in the range from 0 to
   <function>mysql_num_rows</function> - 1. However if the result set 
   is empty (<function>mysql_num_rows</function> == 0), a seek to 0 will 
   fail with a <link linkend="e-warning">E_WARNING</link> and 
   <function>mysql_data_seek</function> will return &false;.
  </para>
 </refsect1>
 
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    &mysql.result.description;
    <varlistentry>
     <term><parameter>row_number</parameter></term>
     <listitem>
      <para>
       The desired row number of the new result pointer.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>mysql_data_seek</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('sample_db');
if (!$db_selected) {
    die('Could not select database: ' . mysql_error());
}
$query = 'SELECT last_name, first_name FROM friends';
$result = mysql_query($query);
if (!$result) {
    die('Query failed: ' . mysql_error());
}
/* fetch rows in reverse order */
for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
    if (!mysql_data_seek($result, $i)) {
        echo "Cannot seek to row $i: " . mysql_error() . "\n";
        continue;
    }

    if (!($row = mysql_fetch_assoc($result))) {
        continue;
    }

    echo $row['last_name'] . ' ' . $row['first_name'] . "<br />\n";
}

mysql_free_result($result);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    The function <function>mysql_data_seek</function> can be used in
    conjunction only with <function>mysql_query</function>, not with
    <function>mysql_unbuffered_query</function>. 
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mysql_query</function></member>
    <member><function>mysql_num_rows</function></member>
    <member><function>mysql_fetch_row</function></member>
    <member><function>mysql_fetch_assoc</function></member>
    <member><function>mysql_fetch_array</function></member>
    <member><function>mysql_fetch_object</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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