php – Yii：如何在GROUP BY与CDbCriteria之前进行ORDER BY？

SELECT * FROM (
    SELECT * FROM message ORDER BY added_on DESC
) as m WHERE receiver_id = 2 GROUP BY sender_id ORDER BY priority_id DESC;

我知道如何使用findAllBySql来做到这一点：

$this->findAllBySql(
    'SELECT * FROM (
        SELECT * FROM message ORDER BY added_on DESC
     ) as m WHERE receiver_id = :receiverId 
     GROUP BY sender_id 
     ORDER BY priority_id DESC',array('receiverId' => $userId));

但是我想知道是否有任何方法可以使用CDbCriteria执行此操作,因为以下代码当然不起作用：

$criteria = new CDbCriteria();
$criteria->condition = 'receiver_id = :receiverId';
$criteria->group = 'sender_id';
$criteria->order = 'priority_id DESC,added_on DESC';
$criteria->params = array('receiverId' => $userId);

谢谢.