Question

三张表查询出选了两门课以上的学生,学生表课程表选课表sql怎么写

Answer 1

学生表：student（学号：sno、姓名：sname、性别：sgender、年龄：sage）
课程表：couse （课程编号：cno、课程名称：cname）
选课表：sc（学号：sno、课程编号：cno、成绩：marks）
SELECT s.sno ,
s.sname ,
c.cname
FROM student s
INNER JOIN sc t1 ON t1.sno = s.sno
INNER JOIN couse c ON sc.cno = c.cno
WHERE s.sno IN ( SELECT t.sno
FROM sc t
GROUP BY t.sno
HAVING COUNT(t.cno) = 2 )

Answer 2

select s.sno,s.name from student s
where s.sno in(select sno from score sc group by sc.cno having count(sc.sno)>2 )