教材上答案是:
SELECT DISTINCT Sno
FROM SC SCX
WHERE NOT EXISTS
(SELECT *
FROM SC SCY
WHERE SCY.Sno = ' 200215122 ' AND
NOT EXISTS
(SELECT *
FROM SC SCZ
WHERE SCZ.Sno=SCX.Sno AND
SCZ.Cno=SCY.Cno));
不知道能否转换成求解学生选的课程包含了学生200215122选的课程,采用in谓词怎么写?
SELECT DISTINCT Sno
FROM SC SCX
WHERE NOT EXISTS
(SELECT *
FROM SC SCY
WHERE SCY.Sno = ' 200215122 ' AND
NOT EXISTS
(SELECT *
FROM SC SCZ
WHERE SCZ.Sno=SCX.Sno AND
SCZ.Cno=SCY.Cno));
不知道能否转换成求解学生选的课程包含了学生200215122选的课程,采用in谓词怎么写?
WHERE Sno in(SELECT sno FROM SC SCY WHERE SCY.Sno = ' 200215122 ' AND
cno in(SELECT cno FROM SC SCZ WHERE SCZ.Sno=SCX.Sno AND SCZ.Cno=SCY.Cno))