Doctrine 如何正确使用条令中的IF语句并选择AS？

我无法按“uid”分组，好像uid根本不起作用

如果我尝试通过->getSqlQuery检索生成的sql，并直接在Mysql中进行尝试，它会工作

$query = Doctrine_Query::create()
->select('IF(m.sender_id = ?, m.receiver_id, m.sender_id) AS uid', $my_id)
->from('Message m')
->where('m.receiver_id = ? OR m.sender_id = ?', array($my_id,$my_id))
->groupBy('uid')

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翻译后的查询在DBMS中工作吗？生成了什么？@DRCOLOSOS生成的查询在DBMS中工作，如果我通过->getSqlQuery检索它，我正在编辑帖子以显示您找到解决方案的查询？您能给代码添加一些解释吗？

SELECT IF(s.sender_id = 1, s.receiver_id, s.sender_id) AS s__0 
FROM message s 
WHERE (s.receiver_id = 1 OR s.sender_id = 1) GROUP BY s__0

$em = $this->getDoctrine()->getEntityManager();
$qb = $em->createQueryBuilder();
$q = $qb
      ->select("c.id")
      ->addSelect("CASE WHEN (c.parent IS NULL) THEN c.name ELSE 'something' END")
      ->from("MyBundle:Category", "c")
      ->leftJoin("c.parent", "t");

echo $q->getQuery()->getSQL();