Question

在Symfony 2中，我尝试进行子选择以从表中获取总计数。我每次收到以下错误：SQLSTATE[21000]: Cardinality violation: 1242 Subquery returns more than 1 row。为什么我的声明中的GROUP BY不起作用？

$dql = " SELECT u.id as UserId, (
                          SELECT  count(mtp.id)
                          FROM    Site\MyBundle\Entity\MessageThread mtp
                          WHERE   mtp.status=0
                          GROUP BY mtp.message
                    ) as MessageThreadCountPending
                    FROM      Site\UserBundle\Entity\Entity\User u
                    WHERE     u.id=:id
                    ";

示例MessageThread表

id | message | status | text 
-------------------------------------------
1  | 1       | 0      | Blah blah blah
2  | 2       | 0      | Blah blah blah
3  | 2       | 0      | Blah blah blah
4  | 3       | 0      | Blah blah blah

期望的结果将由3

感谢您的反馈！

Answer 1

一个简单的解决方法是删除子查询中的group by：

SELECT u.id as UserId,
       (SELECT count(mtp.id)
        FROM Site\MyBundle\Entity\MessageThread mtp
        WHERE mtp.status = 0
       ) as MessageThreadCountPending
FROM Site\UserBundle\Entity\Entity\User u
WHERE u.id = :id;

虽然这可以修复症状，但我怀疑你在子查询中需要某种关联子句。我猜是这样的：

        WHERE mtp.status = 0 and mtp.user_id = u.id

Syfmony Group By Sub选择错误

1 个答案: