HQL子查询不支持from

午，跨表查询，写了很长的hql语句，就是出错！后来上网查查，方知hql语句的from不支持子查询，where支持！

如： select a from A a,(select b from B b,C c where b.id=c.id) d 
       where a.id=d.id; 
  改为→select a from A a where a.id in (select b.id from B b,C c 
       where b.id=c.id);