150分求教VFP SQL语句

[xymdk]

有3个表:
s(xh,xm)(学号\姓名)
c(kch,khm,ls)(课程号\课程名\老师)
sc(xh,kch,cj)(学号\课程好\成绩)
现在要查询的是:选修全部课程的学生姓名.
select s.xm
from s
where not exists
(sele *
from sc
where not exists
(sele *
from c
where sc.xh=s.xh and sc.kch=c.kch));

VFP6中写此语句,说嵌套太深,有简单的语句实现或怎么实现?

[huntertiger]

select sc.xh,s.xm from sc join s on sc.xh=s.xh group by sc.xh having count(*)=(select count(*) from c group by kch)

[mgan]

sele count(kch)as a1 from c into cursor t1
sele max(a1) as maxch1 form t1 into array c1
sele cout(kch) as a2 form sc group by kch into cursor t2
sele max(a2) as maxkch2 form t2 into array c2
sele xh,xm form a where c1=c2


这样 麻烦一点但是不会嵌套太深

[520zyb]

select count(kch) as num from c into cursor num
select s.xh,xm,kch from s,sc where s.xh=sc.xh into cursor t1
select xm,count(xm) from t1 where count(xm)=num.num group by xm

[520zyb]

更改最后一句：select xm,count(xh) from t1 where count(xh)=num.num group by xh

[xymdk]

都不是好办法?还有更好的嘛?一个语句可以解决嘛?

[ishxb]

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