Select user dialogs

gistfile1.sql

SELECT * FROM `messages` JOIN (SELECT if(sender_id = 12, receiver_id, sender_id) AS user_id_other, MAX(cdate) as date_time_max FROM `messages` WHERE sender_id = 12 OR receiver_id = 12 GROUP BY IF(sender_id = 12, receiver_id, sender_id)) as t ON if(sender_id = 12, receiver_id, sender_id) = user_id_other AND cdate = date_time_max JOIN `users` ON `users`.id = IF(`messages`.sender_id = 12, `messages`.receiver_id, `messages`.sender_id) WHERE sender_id = 12 OR receiver_id = 12 ORDER BY cdate DESC LIMIT 11 OFFSET 0


PHP
    public static function getListByUser($user_id, $limit) {
                $query = "`messages`
                             JOIN (SELECT if(sender_id = {$user_id}, receiver_id, sender_id) AS user_id_other, MAX(cdate) as date_time_max FROM `messages`
                             WHERE sender_id = {$user_id} OR receiver_id = {$user_id}
                             GROUP BY IF(sender_id = {$user_id}, receiver_id, sender_id)) as t ON if(sender_id = {$user_id}, receiver_id, sender_id) = user_id_other AND cdate = date_time_max
                             JOIN `users` ON `users`.id = IF(`messages`.sender_id = {$user_id}, `messages`.receiver_id, `messages`.sender_id)
                             WHERE sender_id = {$user_id} OR receiver_id = {$user_id}
                             ORDER BY cdate DESC";

                return self::getList(array(
                                'select' => 'messages.message, messages.id,messages.cdate,messages.isRead, users.user_name,users.avaToken,users.id as userId',
                                'from' => $query,
                        ),true,true,$limit);
        }