Chyba při dotazu na databázi

<?php
    $sql = mysql_query('SELECT id, author, title, text,  publish_time '.'FROM articles ORDER BY publish_time DESC');
    while($res = mysql_fetch_array($sql))
    while($rec = mysql_fetch_row($res)) { // ŘÁDEK 25 U KTERÉHO SE VYPISUJE CHYBA
?>

<?php
    $sql = mysql_query('SELECT id, author, title, text,  publish_time FROM articles ORDER BY publish_time DESC');
    while($res = mysql_fetch_array($sql)){
    echo $res['id'].'<br>';
    echo $res['text'].'<br>';
    }
 
?>

    <item>
      <title><?php echo $rec["title"]; ?></title>
      <link>http://www.domena.com/<?php echo $rec["id"]; ?>/</link>
      <guid>http://www.domena.com/<?php echo $rec["id"]; ?>/</guid>
      <description><?php echo htmlspecialchars(strip_tags($rec["text"])); ?>/description>
      <pubDate><?php echo gmdate("D, d M Y H:i:s", $rec["publish_time"])." GMT"; ?></pubDate>
    </item>
<?php
    }
?>
   </channel>
</rss>