Question

这几题的sql语句怎么写？

如题。全部表的字段名已经在图片中给出

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Answer 1

12.

select distinct s.sn, c.cn, tTemp.tn from sc
left join s on s.sno = sc.sno
left join c on c.cno = sc.cno
left join --课程对应的老师
(select t.dept, t.tn, tc.cno from tc
left join t on tc.tno = t.tno) as tcTemp on tcTemp.cno = sc.cno
where s.dept = tTemp.dept