php-doc-en/reference/mysqli/functions/mysqli-affected-rows.xml

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  <refentry id="function.mysqli-affected-rows">
   <refnamediv>
    <refname>mysqli_affected_rows</refname>
    <refpurpose>Gets the number of affected rows in a previous MySQL operation</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>mixed</type><methodname>mysqli_affected_rows</methodname>
      <methodparam><type>object</type><parameter>link</parameter></methodparam>
     </methodsynopsis>
    <para>
     <function>mysqli_affected_rows</function> returns the number of rows affected by the last
     INSERT, UPDATE, or DELETE query associated with the provided <parameter>link</parameter>
     parameter. If the last query was invalid, this function will return -1.
    </para>
    <note>
     <para>
      When deleting the entire contents of a table (i.e. 'DELETE FROM foo'), this function will
      not return the number of rows that were actually deleted. 
     </para>
    </note>
    <para>
     The <function>mysqli_affected_rows</function> function only works with queries which modify
     a table. In order to return the number of rows from a SELECT query, use the
     <function>mysqli_num_rows</function> function instead.
    </para>
    <para>
     <example>
      <title>Delete-Query</title>
      <para>Procedural style:</para>
      <programlisting role="php">
<![CDATA[
<?php
    /* connect to database */
    $link = mysqli_connect("localhost", "mysql_user", "mysql_password", "mydb") or
        die("Could not connect: " . mysqli_connect_error());
    
    /* this should return the correct numbers of deleted records */
    mysqli_query($link, "DELETE FROM mytable WHERE id < 10");
    printf ("Records deleted: %2d\n", mysqli_affected_rows($link));

    /* without a where clause in a delete statement, it should return 0 */
    mysqli_query($link, "DELETE FROM mytable");
    printf ("Records deleted: %2d\n", mysqli_affected_rows($link));

    /* close connection */
    mysqli_close($link);
?>
]]>
      </programlisting>
      <para>Object oriented style:</para>
      <programlisting>
<![CDATA[
<?php
    /* connect to database */
    $mysql = mysqli_connect("localhost", "mysql_user", "mysql_password", "mydb") or
        die("Could not connect: " . mysqli_connect_error());
    
    /* this should return the correct numbers of deleted records */
    $mysql->query("DELETE FROM mytable WHERE id < 10");
    printf ("Records deleted: %2d\n", $mysql->affected_rows());

    /* without a where clause in a delete statement, it should return 0 */
    $mysql->query("DELETE FROM mytable");
    printf ("Records deleted: %2d\n", $mysql->affected_rows());

    /* close connection */
    $mysql->close();
?>
]]>
      </programlisting>
      <para>
       The above examples would produce the following output:
       <screen>
<![CDATA[
Records deleted: 10
Records deleted:  0
]]>
       </screen>
      </para>
     </example>
     <example>
      <title>Update-Query</title>
      <para>Procedural style:</para>
      <programlisting role="php">
<![CDATA[
<?php
    /* connect to database */
    $link = mysqli_connect("localhost", "mysql_user", "mysql_password", "mydb") or
        die("Could not connect: " . mysqli_connect_error());
        
    /* Update records */
    mysqli_query($link, "UPDATE mytable SET used=1 WHERE id < 10");
    printf ("Updated records: %d\n", mysqli_affected_rows($link));

    /* close connection */
    mysqli_close($link);
?>
]]>
      </programlisting>
      <para>Object oriented style:</para>
      <programlisting role="php">
<![CDATA[
<?php
    /* connect to database */
    $mysql = mysqli_connect("localhost", "mysql_user", "mysql_password", "mydb") or
        die("Could not connect: " . mysqli_connect_error());
        
    /* Update records */
    $mysql->query("UPDATE mytable SET used=1 WHERE id < 10");
    printf ("Updated records: %d\n", $mysql->affected_rows($link));

    /* close connection */
    mysql->close($link);
?>
]]>
      </programlisting>
      <para>
       The above examples would produce the following output:
       <screen>
<![CDATA[
Updated Records: 10
]]>
       </screen>
      </para>
     </example> 
    </para>
    <para>
     See also: <function>mysqli_num_rows</function>,
     <function>mysqli_info</function>.
    </para>
   </refsect1>
  </refentry>

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