第9题: 等价于修了和01相同颗数,01没有修他们就没有修
select sid from sc where CId not in(select cid from course where cid not in (select cid from sc where sid = '01')) group by sid
having count(sid) = (select count(sid) from sc where sid = '01');
50道SQL练习题及答案与详细分析网上流传较广的50道SQL训练,奋斗了不知道多久终于写完了。前18道题的难度依次递增,从19题开始的后半部分算是循环练习和额外function的附加练习,难度恢复到普通状态。...