哎呀呀，脑子短路突然不会做了，明天考试

学生表student，学号sno，课程表course，课程号cno，选修表sc，sdept，grade，ssex，sage，sname，cname，需要用到的差不多就是这些吧，求大神

这世界很复杂，混肴我想说的话。我不懂太复杂的文法。。
　　　--来自火星的七七

根据这些属性自己建表？

表student的属性：sno，sdept，ssex，sage，sname
表course属性：cno，cname
表sc属性：sno，cno，grade

8.select student.sno,student.sname,avg(grade)
from student,sc
where sex='男'
group by sno
having avg(grade)>60;

9.select sno
from sc
group by sno
having avg(grade)>=all (
select avg(grade)
from sc
group by sno
);

10.select avg(sage)
from student
where sdept='CS'
group by ssex;

睡觉了。

14.select cno
from course
where cno in (
select cno
from sc);

select cno
from sc
group by cno
having count(sno)=(
select count(sno)
from student);

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