java - 如何使用 JPA 编写复杂的连接查询

Question

如何使用 JPA 编写这种复杂的连接查询，我在下面指出的一些语法不适用于 JPA。我已经使用它们来演示应该构建 sql 查询的方式，对此深表歉意。

SELECT Result1.name1, Result1.count1, Result2.name2, Result2.count2 FROM (
    SELECT 
        taskOne.user.name AS name1,
        COUNT(taskOne.taskId) AS count1
    FROM
        Task AS taskOne
    INNER JOIN
        taskOne.defect AS defectOne
    WHERE (
        defectOne.defId = taskOne.defect.defId
        AND
        taskOne.taskCategory.tcaId = 1
    )
    GROUP BY
        taskOne.user.usId
) AS Result1
FULL JOIN (
    SELECT
        taskTwo.user.name AS name2,
        COUNT(taskTwo.taskId) AS count2
    FROM Task AS taskTwo
    INNER JOIN taskTwo.defect AS defectTwo
    WHERE (
        defectTwo.defId = taskTwo.defect.defId
        AND
        taskTwo.taskCategory.tcaId = 2
    )
    GROUP BY taskTwo.user.usId
)
AS Result12
WHERE Result1.name1 = Result12.name2

Answer 1

选择对象需要 JPQL。您的查询似乎非常复杂，我建议使用 native SQL 查询或对其进行简化。

JPQL 不支持 from 子句中的子选择。