急急急!!用SQL语句编写 求!!!!!

(b)select c.[课程名],[平均成绩]=avg(s.[成绩]) from 学生选课 sinner join 课程 c on s.[课程号]=c.[课程号]inner join 学生 st on st.[学号]=s.[学号]where st.[系编号]=001group by c.[课程号],c.[课程名]order by c.[课程号] desc<5>select [学号],[科目数]=count(1) from 学生选课 where [成绩]>80 group by [学号] order by [学号],[科目数]<6>select s.[姓名],s.[年龄],l.[系名] from 学生 sinner join 系 l on s.[系编号]=l.[系编号]where (select count([课程号]) from 学生选课 where [学号]=s.[学号])>2<7>select [学号] from 学生选课 where [成绩]>80 group by [学号]having count([学号])>11、ALTER proc proc_GetStuInfoByStuNo@学号 varchar(10)asselect c.[课程名],s.[课程号],s.[成绩]from 学生选课 sinner join 课程 c on s.[课程号]=c.[课程号]where s.[学号]=@学号go2、exec proc_GetStuInfoByStuNo '970001' 收起