mysql_query("DELETE FROM module_comments WHERE id='$del'"); do { $tmpq=mysql_query("SELECT * FROM module_comments"); $arr=array(); while($tmpd=mysql_fetch_array($tmpq,MYSQL_ASSOC)){ $arr[]=$tmpd['id']; print_r($arr); } } while (mysql_query("DELETE FROM module_comments WHERE parent NOT IN (".implode(",", $arr).")"));