提高hql中子查询的速度

in

 

query = session.createQuery("FROM TdResult where Dbfname='"
+ redf + "' and Recordnum in(select Recordnum from TdResult where "+ keyitem +" and content <> '') group by content order by "+ordf);

转化成

List ls=HibernateSessionFactory.getSession().createQuery("select Recordnum from TdResult where "+ keyitem +" and content <> ''").list();
query = session.createQuery("FROM TdResult where Dbfname='"
+ redf + "' and Recordnum in (:mynum) group by content order by "+ordf).setParameterList("mynum",ls);