hql统计查询（八）

(1)统计条数
List list = session.createQuery("select count(*) from Student").list();
Long count = (Long)list.get(0);
System.out.println("count="+count);   
}
或者（前提必须是唯一值）
Long count = (Long)session.createQuery("select count(*) from Student").uniqueResult();
System.out.println("count="+count);   
}
或者(即使不是唯一值也不会出问题)
Long count = (Long)session.createQuery("select count(*) from Student").setMaxResults(1).uniqueResult();
System.out.println("count="+count);   
}
(2)分组统计：聚会函数必须分组
String hql = "select c.name,count(s) from Classes c join c.students s group by c.name order by c.name";
List students = session.createQuery(hql).list();
for(int i=0;i<students.size();i++){
Object[] obj = (Object[])students.get(i);
System.out.println(obj[0] +"," +obj[1]);
}