Придумал Йа крч.
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<?
$max = $db -> dbcount('MAX(`id`)','users');
$element=0;
$msg.='<b>Пользователи:</b><br/>';
$base = $db -> query("SELECT `login` FROM `users` ORDER BY `id` DESC");
while ($assoc = $base -> fetch_assoc()) {
$element++;
$msg.=$assoc['login'];
if($max>$element)$msg.=',';
}
?>