$sql = 'UPDATE s_user_message SET gonderen_okundu=1 WHERE c_id=\''.$cekilanid.'\' AND m_to="';

if ($verial->m_to==$conv->c_from){
	$sql.=$conv->c_from;
} else if ($verial->m_to==$conv->c_to){
 	$sql.=$conv->c_to;
}
$sql.='" ORDER BY m_id DESC LIMIT 1';

$db->query($sql) ;