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[倒大霉的上帝]

数据如下：
ID State Name
1 1 last
2 2 last
3 4 last
4 1 first
5 2 first
6 1 New

要求根据同名的Name 取 State最大的记录 结果如下

3 4 last
5 2 first
6 1 New

[albert_sky]

select name,MAX(state) as state from T
group by name

[-狙击手-]

select *
from ta a
where not exists(select 1 from ta where name = a.name and state > a.state)

[--小F--]

select * from  tb t where State=(select max(State) from tb where name=t.name)

[erpvsyang]

select * from tb t where state in (select max(state)from tb where name=t.name)

[--小F--]

----------------------------------------------------------------
-- Author  :fredrickhu(小F，向高手学习)
-- Date    :2010-06-13 15:29:01
-- Version:
--      Microsoft SQL Server 2005 - 9.00.4035.00 (Intel X86) 
--	Nov 24 2008 13:01:59 
--	Copyright (c) 1988-2005 Microsoft Corporation
--	Developer Edition on Windows NT 5.1 (Build 2600: Service Pack 3)
--
----------------------------------------------------------------
--> 测试数据：[tb]
if object_id('[tb]') is not null drop table [tb]
go 
create table [tb]([ID] int,[State] int,[Name] varchar(5))
insert [tb]
select 1,1,'last' union all
select 2,2,'last' union all
select 3,4,'last' union all
select 4,1,'first' union all
select 5,2,'first' union all
select 6,1,'New'
--------------开始查询--------------------------
select * from  tb t where State=(select max(State) from tb where name=t.name) order by 1
----------------结果----------------------------
/*ID          State       Name
----------- ----------- -----
3           4           last
5           2           first
6           1           New

(3 行受影响)
*/

[zmydebug]

一楼的就行了，取出来就都只有一条最大的记录

[振乾]

IF(OBJECT_ID('test') IS NOT NULL) 
   DROP TABLE test
CREATE TABLE Test
(
	ID INT IDENTITY(1,1) PRIMARY KEY,
	STATE INT,
	NAME VARCHAR(20)
)
INSERT test(STATE,name) VALUES(1,'last')
INSERT test(STATE,name) VALUES(2,'last')
INSERT test(STATE,name) VALUES(4,'last') 
INSERT test(STATE,name) VALUES(1,'first')
INSERT test(STATE,name) VALUES(2,'first')
INSERT test(STATE,name) VALUES(1,'New')

SELECT * FROM Test t 

SELECT * FROM test WHERE id IN (SELECT  MAX(id) FROM test GROUP BY NAME )

[永生天地]

select * from tb t
where not exists(select 1 from tb where name=t.name and state>t.state)

[黄_瓜]

--处理表重复记录(查询和删除)
/******************************************************************************************************************************************************
1、Num、Name相同的重复值记录,没有大小关系只保留一条
2、Name相同,ID有大小关系时,保留大或小其中一个记录
整理人：中国风(Roy)

日期:2008.06.06
******************************************************************************************************************************************************/

--1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)

--> --> (Roy)生成測試數據
 
if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go


--I、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(注:ID为唯一时可用):
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

方法11:

select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID) as MinID from #T a)T where MinID=1

生成结果:
/*
ID          Name Memo
----------- ---- ----
1           A    A1
4           B    B1

(2 行受影响)
*/


--II、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(注:ID为唯一时可用):
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

方法11:
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID desc) as MinID from #T a)T where MinID=1

生成结果2:
/*
ID          Name Memo
----------- ---- ----
3           A    A3
5           B    B2

(2 行受影响)
*/



--2、删除重复记录有大小关系时,保留大或小其中一个记录


--> --> (Roy)生成測試數據

if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go

--I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
方法1:
delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID<a.ID)

方法2:
delete a  from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null

方法3:
delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)

方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select min(ID)from #T group by Name)

方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0

方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)

方法7:
delete a from #T a where ID>any(select ID from #T where Name=a.Name)



select * from #T

生成结果:
/*
ID          Name Memo
----------- ---- ----
1           A    A1
4           B    B1

(2 行受影响)
*/


--II、Name相同ID保留最大的一条记录:

方法1:
delete a from #T a where  exists(select 1 from #T where Name=a.Name and ID>a.ID)

方法2:
delete a  from #T a left join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null

方法3:
delete a from #T a where ID not in (select max(ID) from #T where Name=a.Name)

方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select max(ID)from #T group by Name)

方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)>0

方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID desc)

方法7:
delete a from #T a where ID<any(select ID from #T where Name=a.Name)


select * from #T
/*
ID          Name Memo
----------- ---- ----
3           A    A3
5           B    B2

(2 行受影响)
*/

[crazyrcd]

[Quote=引用 1 楼 albert_sky 的回复:]

SQL code

select name,MAX(state) as state from T
group by name
[/Quote]
顶

[永生天地]

select * from test20100613 t
where not exists(select 1 from test20100613 where name=t.name and state>t.state)
/*
ID          STATE       NAME                 
----------- ----------- -------------------- 
3           4           last
5           2           first
6           1           New

（所影响的行数为 3 行）
*/

--测试表
IF(OBJECT_ID('test20100613') IS NOT NULL) 
   DROP TABLE test20100613
CREATE TABLE test20100613
(
    ID INT IDENTITY(1,1) PRIMARY KEY,
    STATE INT,
    NAME VARCHAR(20)
)
INSERT test20100613(STATE,name) VALUES(1,'last')
INSERT test20100613(STATE,name) VALUES(2,'last')
INSERT test20100613(STATE,name) VALUES(4,'last') 
INSERT test20100613(STATE,name) VALUES(1,'first')
INSERT test20100613(STATE,name) VALUES(2,'first')
INSERT test20100613(STATE,name) VALUES(1,'New')

[振乾]

 数据如下：
ID State Name
1 1 last
2 2 last
3 4 last
4 1 first
5 2 first
6 1 New

要求根据同名的Name 取 State最大的记录 结果如下

3 4 last
5 2 first
6 1 New

IF(OBJECT_ID('test') IS NOT NULL) 
   DROP TABLE test
CREATE TABLE Test
(
	ID INT IDENTITY(1,1) PRIMARY KEY,
	STATE INT,
	NAME VARCHAR(20)
)
INSERT test(STATE,name) VALUES(1,'last')
INSERT test(STATE,name) VALUES(2,'last')
INSERT test(STATE,name) VALUES(4,'last') 
INSERT test(STATE,name) VALUES(1,'first')
INSERT test(STATE,name) VALUES(2,'first')
INSERT test(STATE,name) VALUES(1,'New')

SELECT * FROM Test t 
--SELECT * FROM test WHERE id IN (SELECT  MAX(id) FROM test GROUP BY NAME ) 
 
 --方法一：
 SELECT * FROM test t WHERE STATE=(SELECT MAX(STATE) FROM test WHERE NAME=t.[NAME] )
 --方法二：
 SELECT * FROM test t WHERE NOT EXISTS (SELECT 1 FROM tb WHERE NAME=t.name AND state>t.[STATE])
 

[倒大霉的上帝]

非常感谢大家的踊跃回答。采用了小F的方法。同时非常感谢小爱和小生