Question

我有一个实体组，该实体组要使用@Formula进行计算。

还有其他三个具有该实体外键的实体，而我要计算的是有多少实体依赖于每个Group实体，因此公式如下所示：

public class Group {

...

@Formula("(select count (distinct (s.id)) + count(distinct(ses.id)) + count (distinct(u.id))
    from section s, session ses, user u, group_user gu
    where s.group_id = id and ses.group_id = id and gu.user_id = u.id and
          gu.group_id = id )")
    private int dependencies;
}

但是当我在Group上执行findAll时，它会抛出异常：

ORA-00904: "GROUP0_"."COUNT": invalid identifier

生成的SQL看起来很奇怪，像这样：

    Hibernate: select * from ( select distinct group0_.id as id1_8_, group0_.active as active2_8_, group0_.code as code3_8_, 
... 
(select group0_.count (distinct (s.id)) + count(distinct(ses.id)) + group0_.count (distinct(u.id)) from section s, session ses, user u, group_user gu where s.group_id = group0_.id and ses.group_id = group0_.id and gu.user_id = u.id and gu.group_id = group0_.id ) as formula1_ 
from group group0_ where 1=1 order by group0_.code asc ) where rownum <= ?

如何编写公式以使其起作用？

Answer 1

最后，这只是一个愚蠢的问题：count和（之间的差距，如果我写公式：

@Formula("(select count(distinct (s.id)) + count(distinct(ses.id)) + count(distinct(u.id))
    from section s, session ses, user u, group_user gu
    where s.group_id = id and ses.group_id = id and gu.user_id = u.id and
          gu.group_id = id )")

有效！

@Formula注释不了解“计数”

1 个答案: