hibernate createSqlQuery 多表查询 没有返回预期对象数组有关问题

String sql = "  select wk.a1 ,wk.a2 , {ex.*}  from " +                " (select distinct a1,a2 from A ) as wk  join mms_cell {ex} on {ex}.a1= wk.a1 " +                " order by wk.a1,wk.a2,{ex}.mydate";   Query query = getSession().createSQLQuery(sql).                             addEntity("ex",User.class);   List<Object[]> list = query.list();  

Query query = getSession().createSQLQuery(sql).addScalar("a1",Hibernate.STRING).addScalar("a2",Hibernate.STRING).                          addEntity("ex",User.class);