数据库的多表连查

学生表

课程表

老师表

1.查询sc表中对应何昊老师所授课程的女生信息

select stu.sno,stu.sname,stu.age,stu.sex from sc inner join cct on sc.cno = cct.Cno inner join stu on sc.sno = stu.sno where Cteacher = '何昊' and sex = '女';

2.找出没有选修过何老师的课程的所有学生姓名

select stu.sname from stu where not exists(select * from sc,cct where sc.cno = cct.Cno and cct.cteacher='何昊' and sc.sno=stu.sno);

3.列出有不及格课程（成绩小于60）的学生姓名

select DISTINCT(stu.sname) from sc inner join stu on sc.sno = stu.sno where sc.scgrade < '60';