+-----------+-------+------+------+-------+
-- 查询选修了‘信息系统’的学生信息(先查出信息系统的课程号cno,再查处所有选课信息,再查出学生信息)
-- 同样,也是不相关子查询
SELECT * FROM student WHERE sno IN (
SELECT sno FROM sc WHERE cno IN (
SELECT cno FROM course WHERE cname='信息系统'
)
)
+-----------+-------+------+------+-------+
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……