休眠条件 MAX of 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，但我得到了 pointsum 未找到的属性

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();

提前谢谢你！

Answer 1

在 hql 中不支持

from 子句中的子查询在 hql 中可能是不可能的。 见https://docs.jboss.org/hibernate/stable/core.old/reference/en/html/queryhql-subqueries.html

请注意，HQL 子查询可能只出现在 select 或 where 条款。

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其他选项

我有两个建议来解决这个问题：排序和限制结果，或者创建一个视图。

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视图并从中选择

   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）。