java - Hibernate 标准 MAX 或 SUM

Question

如何使用标准(JAVA)实现此 HQL

"SELECT MAX(pointsum) FROM (SELECT SUM(h.point) as pointsum FROM HealthPoint h WHERE h.player.partner = :partner GROUP BY h.player)"

我已经对此进行了测试，但我得到了它，但我找不到属性pointsum

DetachedCriteria detachedPlayer = DetachedCriteria.forClass(Player.class);
detachedPlayer.add(Restrictions.eq("partner", partner));
detachedPlayer.setProjection(Projections.property("id"));

Criteria criteria = getSessionFactory().getCurrentSession().createCriteria(HealthPoint.class);
criteria.add(Subqueries.propertyIn("player", detachedPlayer));
ProjectionList proj = Projections.projectionList();
proj.add(Projections.sum("point"));
proj.add(Projections.groupProperty("player"));
criteria.setProjection(Projections.alias(proj, "pointsum"));
criteria.setProjection(Projections.max("pointsum"));
return (Integer) criteria.uniqueResult();

提前谢谢您!

Answer 1

hql 不支持

from 子句中的子查询在 hql 中可能不可用。 请参阅https://docs.jboss.org/hibernate/stable/core.old/reference/en/html/queryhql-subqueries.html

Note that HQL subqueries may occur only in the select or where clauses.

<小时/>

其他选项

我有两个建议来解决这个问题:排序并限制结果，或者创建一个 View 。

1. 将结果限制为您想要的结果:

   .createQuery("SELECT SUM(h.point) as pointsum FROM HealthPoint h WHERE h.player.partner = :partner GROUP BY h.player order by pointsum desc")
   .limit(1);
   

2. 在数据库中创建一个 View 并从中进行选择

   create view HealthPointSumsByPlayer 
   as 
     select sum(point), player_id 
     from Health_Points 
     group by player_id;
   

然后从中选择(通过 hql)。