Question

请教一道数据库的题目

题目很简单，但我逻辑搞不好

Answer 1

select student.SId from (select SId,Score from SC where CId=1)student ,(select sid,Score from SC where CId=2)score
where student.Score>score.Score and student.SId=score.SId
SELECT student.SId
FROM ( SELECT SId ,
Score
FROM SC
WHERE CId = 1
) student , --查询出课程一的成绩
( SELECT sid ,
Score
FROM SC
WHERE CId = 2
) score --查询出课程二的成绩
WHERE student.Score > score.Score --查询出课程一比课程二高的成绩学生id
AND student.SId = score.SId; --同一个学生

Answer 2

SELECT  s1.[Sid]
  FROM [SC] s1 
  inner join [SC] s2 on s1.[Sid] = s2.[Sid] and s2.Cid = 'A02'  and s1.score > s2.score and s1.Cid = 'A01'