1 in 子查询

1 use StudentManageDB2 go3 --select StudentName from Students 4 --where StudentId=(select StudentId from ScoreList where SQLServerDB>80)5 select StudentName from Students 6 where StudentId in (select StudentId from ScoreList where SQLServerDB>80)

1 use StudentManageDB2 go3 select StudentId,StudentName from Students4 where StudentId not in(select StudentId from ScoreList)

2.exist 子查询

1 use StudentManageDB 2 go 3 if exists(select * from ScoreList where CSharp<60) 4    print '本次考试内容较难' 5 else 6    print '本次考试内容适中' 7  8 --NOT EXISTS的使用 9 if not exists(select * from ScoreList where CSharp<60)10       print '本次考试内容适中'11 else12       print '本次考试内容较难'