$criteria=new CDbCriteria;
//$criteria->compare('id',$this->id);
$criteria->compare('t.user_id',$this->user_id,true);
$criteria->compare('t.friend_id',$this->friend_id,true);
$criteria->together = true;
$criteria->with=array('user');//needs for sorting
$criteria->compare('user.email', $this->user_email,true);
$criteria->compare('user.first_name', $this->user_first_name,true);
$criteria->compare('user.last_name', $this->user_last_name,true);
$criteria->together = true;
$criteria->with=array('friend');//needs for sorting
$criteria->compare('friend.email', $this->friend_email,true);
$criteria->compare('friend.first_name', $this->friend_first_name,true);
$criteria->compare('friend.last_name', $this->friend_last_name,true);
I made such thing and friend search a working but user not working.