表信息如下:
es_guid email CA_CREATE_DATE
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-5-8 19:54
305CBFFE-FA83-9C7A-9873-311C0F65552B [email protected] 2010-5-8 14:27
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-5-8 14:03
4B684BF8-9AD4-E84A-E75F-DF33F45F6690 [email protected] 2010-5-8 8:04
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-5-8 18:11
824CDCDA-BD75-7E74-38D4-F502ADFB4EC0 [email protected] 2010-5-8 12:28
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-5-8 10:28
6069BE3F-2B0F-9587-11E5-A7E6DC077B9E [email protected] 2010-5-8 9:14
465023B3-100C-3A92-D9DD-45AB9D990E63 [email protected] 2010-5-8 16:07
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-5-8 16:08要求在重复的email选出,最大CA_CREATE_DATE的记录sql执行后的输出结果为:
es_guid email CA_CREATE_DATE
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-5-8 19:54
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-5-8 14:03
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-5-8 18:11
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-5-8 10:28
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-5-8 16:08
es_guid email CA_CREATE_DATE
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-5-8 19:54
305CBFFE-FA83-9C7A-9873-311C0F65552B [email protected] 2010-5-8 14:27
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-5-8 14:03
4B684BF8-9AD4-E84A-E75F-DF33F45F6690 [email protected] 2010-5-8 8:04
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-5-8 18:11
824CDCDA-BD75-7E74-38D4-F502ADFB4EC0 [email protected] 2010-5-8 12:28
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-5-8 10:28
6069BE3F-2B0F-9587-11E5-A7E6DC077B9E [email protected] 2010-5-8 9:14
465023B3-100C-3A92-D9DD-45AB9D990E63 [email protected] 2010-5-8 16:07
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-5-8 16:08要求在重复的email选出,最大CA_CREATE_DATE的记录sql执行后的输出结果为:
es_guid email CA_CREATE_DATE
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-5-8 19:54
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-5-8 14:03
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-5-8 18:11
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-5-8 10:28
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-5-8 16:08
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--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)
*/--3、删除重复记录没有大小关系时,处理重复值
--> --> (Roy)生成測試數據if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([Num] int,[Name] nvarchar(1))
Insert #T
select 1,N'A' union all
select 1,N'A' union all
select 1,N'A' union all
select 2,N'B' union all
select 2,N'B'
Go方法1:
if object_id('Tempdb..#') is not null
drop table #
Select distinct * into # from #T--排除重复记录结果集生成临时表#truncate table #T--清空表insert #T select * from # --把临时表#插入到表#T中--查看结果
select * from #T/*
Num Name
----------- ----
1 A
2 B(2 行受影响)
*/--重新执行测试数据后用方法2
方法2:alter table #T add ID int identity--新增标识列
go
delete a from #T a where exists(select 1 from #T where Num=a.Num and Name=a.Name and ID>a.ID)--只保留一条记录
go
alter table #T drop column ID--删除标识列--查看结果
select * from #T/*
Num Name
----------- ----
1 A
2 B(2 行受影响)*/--重新执行测试数据后用方法3
方法3:
declare Roy_Cursor cursor local for
select count(1)-1,Num,Name from #T group by Num,Name having count(1)>1
declare @con int,@Num int,@Name nvarchar(1)
open Roy_Cursor
fetch next from Roy_Cursor into @con,@Num,@Name
while @@Fetch_status=0
begin
set rowcount @con;
delete #T where Num=@Num and Name=@Name
set rowcount 0;
fetch next from Roy_Cursor into @con,@Num,@Name
end
close Roy_Cursor
deallocate Roy_Cursor--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B(2 行受影响)
*/本文来自CSDN博客,转载请标明出处:http://blog.csdn.net/htl258/archive/2009/04/16/4083040.aspx
from #T a
where exists(select 1 from #T where email=a.email and CA_CREATE_DATE>a.CA_CREATE_DATE)
insert #T
select '4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0','[email protected]','2010-5-8 19:54' union all
select '305CBFFE-FA83-9C7A-9873-311C0F65552B','[email protected]','2010-5-8 14:27' union all
select '685090E8-1211-E328-F106-E284F5F2E8E4','[email protected]','2010-5-8 14:03' union all
select '4B684BF8-9AD4-E84A-E75F-DF33F45F6690','[email protected]','2010-5-8 8:04' union all
select '4F011B4F-5961-6B56-5A70-D004780F394E','[email protected]','2010-5-8 18:11' union all
select '824CDCDA-BD75-7E74-38D4-F502ADFB4EC0','[email protected]','2010-5-8 12:28' union all
select 'B3E112FE-3916-C194-1D7A-75CF0C2342AD','[email protected]','2010-5-8 10:28' union all
select '6069BE3F-2B0F-9587-11E5-A7E6DC077B9E','[email protected]','2010-5-8 9:14' union all
select '465023B3-100C-3A92-D9DD-45AB9D990E63','[email protected]','2010-5-8 16:07' union all
select 'B411A606-C510-ECBD-563A-E29636621C32','[email protected]','2010-5-8 16:08'
delete a from #T a where exists(select 1 from #T where email=a.email and CA_CREATE_DATE>a.CA_CREATE_DATE)select * from #T/*es_guid email CA_CREATE_DATE
------------------------------------ ---------------------------------------- ------------------------------------------------------
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-05-08 19:54:00.000
305CBFFE-FA83-9C7A-9873-311C0F65552B [email protected] 2010-05-08 14:27:00.000
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-05-08 14:03:00.000
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-05-08 18:11:00.000
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-05-08 10:28:00.000
6069BE3F-2B0F-9587-11E5-A7E6DC077B9E [email protected] 2010-05-08 09:14:00.000
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-05-08 16:08:00.000(所影响的行数为 7 行)*/
-- Author : htl258(Tony)
-- Date : 2010-05-12 12:04:18
-- Version: Microsoft SQL Server 2008 (RTM) - 10.0.1600.22 (Intel X86)
-- Jul 9 2008 14:43:34
-- Copyright (c) 1988-2008 Microsoft Corporation
-- Developer Edition on Windows NT 5.1 <X86> (Build 2600: Service Pack 3)
-- Blog : http://blog.csdn.net/htl258
------------------------------------------------------------------------------------> 生成测试数据表: [tb]
IF OBJECT_ID('[tb]') IS NOT NULL
DROP TABLE [tb]
GO
CREATE TABLE [tb] ([es_guid] [nvarchar](40),[email] [nvarchar](20),[CA_CREATE_DATE] [datetime])
INSERT INTO [tb]
SELECT '4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0','[email protected]','2010-5-8 19:54' UNION ALL
SELECT '305CBFFE-FA83-9C7A-9873-311C0F65552B','[email protected]','2010-5-8 14:27' UNION ALL
SELECT '685090E8-1211-E328-F106-E284F5F2E8E4','[email protected]','2010-5-8 14:03' UNION ALL
SELECT '4B684BF8-9AD4-E84A-E75F-DF33F45F6690','[email protected]','2010-5-8 8:04' UNION ALL
SELECT '4F011B4F-5961-6B56-5A70-D004780F394E','[email protected]','2010-5-8 18:11' UNION ALL
SELECT '824CDCDA-BD75-7E74-38D4-F502ADFB4EC0','[email protected]','2010-5-8 12:28' UNION ALL
SELECT 'B3E112FE-3916-C194-1D7A-75CF0C2342AD','[email protected]','2010-5-8 10:28' UNION ALL
SELECT '6069BE3F-2B0F-9587-11E5-A7E6DC077B9E','[email protected]','2010-5-8 9:14' UNION ALL
SELECT '465023B3-100C-3A92-D9DD-45AB9D990E63','[email protected]','2010-5-8 16:07' UNION ALL
SELECT 'B411A606-C510-ECBD-563A-E29636621C32','[email protected]','2010-5-8 16:08'SELECT * FROM [tb]-->SQL查询如下:
delete tb where exists(select 1 from tb t where email=tb.email and [CA_CREATE_DATE]>tb.[CA_CREATE_DATE])select * from tb
/*
es_guid email CA_CREATE_DATE
---------------------------------------- -------------------- -----------------------
4CF4D1CE-BDEC-7551-3DAD-EF196408FDD0 [email protected] 2010-05-08 19:54:00.000
305CBFFE-FA83-9C7A-9873-311C0F65552B [email protected] 2010-05-08 14:27:00.000
685090E8-1211-E328-F106-E284F5F2E8E4 [email protected] 2010-05-08 14:03:00.000
4F011B4F-5961-6B56-5A70-D004780F394E [email protected] 2010-05-08 18:11:00.000
B3E112FE-3916-C194-1D7A-75CF0C2342AD [email protected] 2010-05-08 10:28:00.000
6069BE3F-2B0F-9587-11E5-A7E6DC077B9E [email protected] 2010-05-08 09:14:00.000
B411A606-C510-ECBD-563A-E29636621C32 [email protected] 2010-05-08 16:08:00.000(7 行受影响)
*/