学生-课程关系数据库

1、select C# from SC where S#='040011'

2、select S#, SN from S where S# in (select S# from SC where G >= 80 and C# in (select C# from C where CN = '数据库概论'))

3、select S#, count(*), avg(G) from SC group by S# having count(*) >2

1 select * from S

2 select sname, 2014-Sage from S

3 select sname, sage from S where sage between 20 and 22

4 select * from S order by sdept asc, sage desc

5 select S.sno, sname from S, C, SC where S.sno=SC.sno and SC.cno=C.cno and Cname='数据库

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