练习

--12.
select CNO,count(1) as 数量,avg(DEGREE) as 平均值 from T_HQ_SCORE where CNO like '3%'group by CNO having count(1) >=5;

--13.
select SNO from T_HQ_SCORE where DEGREE between 70 and 90;

select SNO from T_HQ_SCORE where DEGREE >70 and DEGREE <90;

--14.
select S.SNAME,C.CNO,C.DEGREE from T_HQ_STUDENT S ,T_HQ_SCORE C where S.SNO =C.SNO;

--15.
select C.SNO,S.CNAME,C.DEGREE from T_HQ_COURSE S,T_HQ_SCORE C where C.CNO = S.CNO;

--16.
select S.SNAME,C.CNAME,SC.DEGREE from T_HQ_STUDENT S,T_HQ_COURSE C,T_HQ_SCORE SC where S.SNO =SC.SNO and SC.CNO = C.CNO;

--17.
select avg(DEGREE) as 平均值 from T_HQ_SCORE where SNO in (select SNO from T_HQ_STUDENT where CLASS = 95033 );