求助! 关于SQL查询的

来源：百度知道 编辑：UC知道 时间：2024/05/24 20:41:14
已知 S(StudentNum, StudentName, Age)
Enroll(StudentNum, CourseNum)
Course(CourseNum, CourseName)

写出该查询的SQL语句:"查询未选‘计算机网络’课程的学生的学号"
后来想出来了
( select StudentNum from Enroll )
except
( select StudentNum from Enroll, Course
where CourseName = '计算机网络')

我照书上搬下来的，一个差不多的题：
select StudentNum
from Enroll
where not exist
( select *
from Course
where CourseNum = Enroll.CourseNum and CourseName = '计算机网络');

select StudentNum from Enroll where Enroll.CourseNum=Course.CourseNum and Course.CourseName<>‘计算机网络’

select s.studentnum from (s inner join enroll as e on s.studentnum=e.studentnum) inner join course as c on e.coursenum=c.coursenum Where c.coursename<>'计算机网络'

SELECT StudentNum FROM s inner join Enroll on S.StudentNum=Enroll.StudentNum inner join Course on Enroll.CourseNum=Course.CourseNum WHERE CourseName<>'计算机网络'

select studentNum where CourseNum!=(select CourseName from Course where CourseName=计算机网络);