统计每个老师的总薪酬

        private void button6_Click(object sender, EventArgs e)
        {
            string s = "select teachers.tname as 姓名,sum(remunerations.wage*courses.ctime) as 总薪酬 ";
            s += "from courses,teachers,remunerations ";
            s += "where courses.tnum=teachers.tnum and teachers.zcnum=remunerations.zcnum ";
            s += "group by teachers.tname order by sum(remunerations.wage*courses.ctime) desc";
            loadLV(listView2, s);
        }