selemet,
$sql_total = "SELECT COUNT(*) FROM `users` WHERE `lastdate` > " . (time() - 300);
$sql_list = "SELECT * FROM `users` WHERE `lastdate` > " . (time() - 300) . " ORDER BY `name` ASC";
$total = mysql_result(mysql_query($sql_total), 0);
$req = mysql_query($sql_list);
if ($total) {
while (($res = mysql_fetch_assoc($req))) {
echo '<div>' . $res['name'] . '</div>';
}
}