分组后取最大值记录的有关问题 MSSQL 2000 的机器

select * from DataTest twhere not exists(select 1 from DataTest where tid=t.tid and dataline>t.dateline)
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SQL code
create table DataTest(TID int null,FID int null,DateLine datetime null)Insert into DataTest(TID,FID,DateLine) values('1','5','2008-02-21 09:03:00')Insert into DataTest(TID,FID,DateLine) values('1','6','2008-02-22 09:03:00')Insert into DataTest(TID,FID,DateLine) values('2','3','2008-06-21 09:03:00')Insert into DataTest(TID,FID,DateLine) values('2','6','2008-02-25 09:03:00')Insert into DataTest(TID,FID,DateLine) values('3','8','2008-02-29 09:03:00')Insert into DataTest(TID,FID,DateLine) values('3','1','2008-05-21 09:03:00')select * from DataTest twhere DateLine=(select max(DateLine) from DataTest where TID=t.TID)order by TID/*TID         FID         DateLine----------- ----------- -----------------------1           6           2008-02-22 09:03:00.0002           3           2008-06-21 09:03:00.0003           1           2008-05-21 09:03:00.000*/
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SQL code
--取大小值/******************************************************************************************************************************************************Name相同ID最小或最大的记录整理人：中国风(Roy)日期:2008.06.06******************************************************************************************************************************************************/--> --> (Roy)生成測試數據 if not object_id('Tempdb..#T') is null    drop table #TGoCreate table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))Insert #Tselect 1,N'A',N'A1' union allselect 2,N'A',N'A2' union allselect 3,N'A',N'A3' union allselect 4,N'B',N'B1' union allselect 5,N'B',N'B2'Go--1、Name相同ID最小的记录(推荐用1,2,3),方法3在SQl05时，效率高于1、2方法1:Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID<a.ID)方法2:select a.* from #T a join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID方法3:select * from #T a where ID=(select min(ID) from #T where Name=a.Name)方法4:select a.* from #T a join #T b on a.Name=b.Name and a.ID>=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 方法5:select * from #T a group by ID,Name,Memo having ID=(select min(ID)from #T where Name=a.Name)方法6:select * from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)=0方法7:select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID)方法8:select * from #T a where ID!>all(select ID from #T where Name=a.Name)方法9:select * from #T a where ID in(select min(ID) from #T group by Name)--SQL2005:方法10:select ID,Name,Memo from (select *,min(ID)over(partition by Name) as MinID from #T a)T where ID=MinID生成结果:/*ID          Name Memo----------- ---- ----1           A    A14           B    B1(2 行受影响)*/--2、Name相同ID最大的记录,与min相反:方法1:Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID>a.ID)方法2:select a.* from #T a join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID方法3:select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID方法4:select a.* from #T a join #T b on a.Name=b.Name and a.ID<=b.ID group by a.ID,a.Name,a.Memo having count(1)=1 方法5:select * from #T a group by ID,Name,Memo having ID=(select max(ID)from #T where Name=a.Name)方法6:select * from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)=0方法7:select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID desc)方法8:select * from #T a where ID!<all(select ID from #T where Name=a.Name)方法9:select * from #T a where ID in(select max(ID) from #T group by Name)--SQL2005:方法10:select ID,Name,Memo from (select *,max(ID)over(partition by Name) as MinID from #T a)T where ID=MinID生成结果2:/*ID          Name Memo----------- ---- ----3           A    A35           B    B2(2 行受影响)*/