查询学生的学号,姓名,平均成绩,要求只显示平均分在80 分以上的学生,按...答:代码如下:select a.学号 , a.姓名 , cast(avg(b.成绩) as decimal(18,2)) 平均成绩 from Student a , sc b where a.学号 = b.学号 group by a.学号 , a.姓名 having cast(avg(b.成绩) as decimal(18,2)) >= 80order by cast(avg(b.成绩) as decimal(18,2)) desc ...