Doctrine orm DQL与Zend Framework 2/Doctrine 2的内部连接

使用此SQL语句，我可以从所有用户获取最新消息：

SELECT  m1.*
FROM    message AS m1
INNER JOIN user
   AS u1
   ON m1.sender_id = u1.user_id
INNER JOIN (
   SELECT   sender_id,
   MAX(dateSent) MaxDate
   FROM     message
   WHERE receiver_id = 4
   GROUP BY sender_id
) AS m2
ON m1.sender_id = m2.sender_id
AND m1.datesent = m2.MaxDate;

这些是我的Zend Framework 2应用程序中的实体：

首先，我明白了。用户可以向其他用户发送消息

/**
 * @ORM\Entity
 * @ORM\Table(name="message")
 */
class Message
{
/**
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="AUTO")
 * @ORM\Column(type="integer")
 */
private $id;

/**
 * @ORM\ManyToOne(targetEntity="Application\Entities\User", inversedBy="messagesSent")
 * @ORM\JoinColumn(referencedColumnName="user_id")
 */
private $sender;

/**
 * @ORM\ManyToOne(targetEntity="Application\Entities\User", inversedBy="messagesReceived")
 * @ORM\JoinColumn(referencedColumnName="user_id")
 */
private $receiver;

/**
 * @ORM\Column(type="string", length=1024)
 */
private $message;

以及此处的用户实体：

/**
 * @ORM\Entity
 * @ORM\Table(name="user")
 */
class User
{
/**
 * @var int
 * @ORM\Id
 * @ORM\Column(type="integer")
 * @ORM\GeneratedValue(strategy="AUTO")
 */
protected $user_id;

我尝试将SQL转换为DQL，得到以下结果：

SELECT  m1.*
FROM    Application\Entities\Message AS m1
INNER JOIN Application\Entities\User AS u1
    WITH m1.sender_id = u1.user_id
INNER JOIN (
    SELECT  sender_id,
    MAX(dateSent) MaxDate
    FROM    Application\Entities\Message
    WHERE receiver_id = 4
    GROUP BY sender_id
) AS m2
WITH m1.sender_id = m2.sender_id
AND m1.datesent = m2.MaxDate;

如果我执行它，我会从条令中得到一个错误：

[Semantical Error] line 0, col 206 near '(
      ': Error: Class '(' is not defined.

---

我做错了什么？

子查询在DQL的条令（据我所知）中不可用。你会写吗

看

public function innerJoin($join, $alias = null, $conditionType = null, $condition = null);