关于SQL分组查询求平均值的问题。

关于SQL分组查询求平均值的问题。

public List findAvgScore(int sid) {
Query query = this
.getSession()
.createQuery(
"select s.year, s.semester, avg(s.score) from Score s where s.student.id=? group by s.year,s.semester")
.setParameter(0, sid);
List list = query.list();
List scoreList = new ArrayList();
for (int i = 0; i < list.size(); i++) {
Object obj[] = (Object[]) list.get(i);
Score score = new Score();
score.setYear(obj[0] + "");
score.setSemester(obj[1] + "");
score.setAvgScore(Double.parseDouble(obj[2].toString()));
scoreList.add(score);
// System.out.println(obj[0] + " " + obj[1] + " " + obj[2]);
}
return scoreList;
}

public List<Double> findAvgScore(int sid) {
return (List<Double>) this.getHibernateTemplate().find("select s.year,s.semester,avg(s.score) from Score s where s.student.id=? group by s.year,s.semester", sid);
}