有学生表Student,选课表SC和课程表Course,要求选修了全部课程的学生的姓名,教材P113是这样写的,有没有人能替我解释一下怎么实现的?
Student(Sno,Sname,Ssex,Sage,Sdept)
SC(Sno,Cno,Grade)
Course(Cno,Cname,Cpno,Ccredit)
程序:
SELECT Sname
FROM Student
WHERE NOT EXISTS
(SELECT *
FROM Course
WHERE NOT EXISTS
(SELECT *
FROM SC
WHERE Sno= Student.Sno
AND Cno= Course.Cno)在线等,谢谢了!!
Student(Sno,Sname,Ssex,Sage,Sdept)
SC(Sno,Cno,Grade)
Course(Cno,Cname,Cpno,Ccredit)
程序:
SELECT Sname
FROM Student
WHERE NOT EXISTS
(SELECT *
FROM Course
WHERE NOT EXISTS
(SELECT *
FROM SC
WHERE Sno= Student.Sno
AND Cno= Course.Cno)在线等,谢谢了!!
解决方案 »
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