Hibernate sum()函数为空的问题

[melodyfair1971]

private String hql = "select sum(TOTAL_TICKETS) from VoteTeacher";
public long getTeacherListMaxSize(final String hql) {
        long size = 0;
        try {
            size = (Long) this.getHibernateTemplate().execute(
                    new HibernateCallback() {

                        public Object doInHibernate(Session session)
                                throws HibernateException, SQLException {
                            Query query = session.createQuery(hql);
                            Long size = (Long) query.list().get(0);
                            return size;

                        }
                    });
        } catch (Exception e) {
        }
        return size;
    }

这样查询,返回的结果总是为0!
但是hql语句改为:

private String hql = "select count(TOTAL_TICKETS) from VoteTeacher";

可以返回记录的总数不为空!

[melodyfair1971]

有大神可以给我指点一下吗.55