HQL 中带有内部联接的子查询

Question

我想从在 Rating 表中具有外键 Movie_id 的 Movies 表中打印标题。在 rating 表中，我们必须根据 movie_id 的出现来获得前 10 个结果。由于 HQL 中不允许限制，所以 setMaxResults 被使用

Query q=session.createQuery("select Title from Movies  as M Inner Join ( SELECT Movie_id, COUNT(*)  FROM Rating  GROUP BY Movie_id ORDER BY COUNT(*) DESC LIMIT 10 ) as R ON M.Movie_id=R.Movie_id").setMaxResults(10);

例外情况是：

java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: ( near line 1, column 59 [select Title from com.rahul.model.Movies  as M Inner Join ( SELECT Movie_id, COUNT(*)  FROM com.rahul.model.Rating  GROUP BY Movie_id ORDER BY COUNT(*) DESC LIMIT 10 ) as R ON M.Movie_id=R.Movie_id]

既然HQL不支持子查询怎么实现呢？

Answer 1

您可以将此查询编写为JOIN/GROUP BY：

select m.Title
from Movies m Inner Join
     Rating r
     on m.Movie_id = r.Movie_id
group by m.Movie_Id, m.Title
order by count(*) desc
limit 10;

Answer 2

已解决

Query q=session.createQuery("select m.title from Movies m Inner Join Rating r on m.movie_id = r.movie_id group by m.movie_id, m.title order by count(*) desc").setMaxResults(10);