1.select Sno,Sname
from Student
where Sdept='数学系';
2.
select distinct Sno
from SC;
3.
select Sno, Grade
from SC
where Cno=1
order by Grade DESC, Sno;
4.
select Sno 学号, Grade*0.8 平均成绩
from SC
where Cno=1
and Grade between 80 and 90;
5.
select *
from Student
where Sdept in ('数学系','计算机')
and Sname like '张%';
6.
select Sno, Cno
from SC
where Grade is null;
7.
select student.*, sc.Cno
from Student student,SC sc
where student.Sno=sc.Sno;
8.
select student.Sno,student.Sname,course.Cname,sc.Grade
from Student student,Course course, SC sc
where student.Sno=sc.Sno
and sc.Cno=course.Cno;
9.
select student.Sno,student.Sname,course.Cname,sc.Grade
from Student student,SC sc,Course course
where student.Sno=sc.Sno
and sc.Cno=course.Cno;
10.
select a.Cno,a.Cname,b.Cpno
from Course a,Course b
where a.Cpno =b.Cno;
11.
select course.Cname 课程名称,avg(sc.Grade) 平均成绩
from Course course, SC sc
where course.Cno=sc.Cno
group by course.Cname
12.
select student.*
from Student student,SC sc, Course course
where student.Sno=sc.Sno
and sc.Cno=course.Cno
and sc.Grade > 80
and sc.Grade in
(
select max(sc.Grade)
from sc
group by sc.Cno
);
