DECLARE @TB TABLE([颜色] NVARCHAR(1), [款式] VARCHAR(4), [批次] VARCHAR(3))
INSERT @TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'SELECT *
FROM @TB AS T
WHERE NOT EXISTS(SELECT * FROM @TB WHERE [颜色]=T.[颜色] AND [款式]=T.[款式] AND [批次]>T.[批次])
/*
颜色 款式 批次
---- ---- ----
红 CT-1 3rd
蓝 CT-1 2nd
红 CT-2 1st
白 CT-2 2nd*/
INSERT @TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'SELECT *
FROM @TB AS T
WHERE NOT EXISTS(SELECT * FROM @TB WHERE [颜色]=T.[颜色] AND [款式]=T.[款式] AND [批次]>T.[批次])
/*
颜色 款式 批次
---- ---- ----
红 CT-1 3rd
蓝 CT-1 2nd
红 CT-2 1st
白 CT-2 2nd*/
INSERT @TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'SELECT [颜色],[款式],MAX([批次]) AS [批次]
FROM @TB AS T
GROUP BY [颜色],[款式]
/*
颜色 款式 批次
---- ---- ----
红 CT-1 3rd
蓝 CT-1 2nd
红 CT-2 1st
白 CT-2 2nd*/
FROM TB AS T
WHERE
NOT EXISTS(SELECT * FROM @TB WHERE [颜色]=T.[颜色] AND [款式]=T.[款式] AND LEFT([批次],1)>LEFT(T.[批次],1))
/******************************************************************************************************************************************************
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)
*/
-- Author :fredrickhu(小F 向高手学习)
-- Date :2009-06-24 10:19:27
----------------------------------------------------------------
--> 测试数据:[ta]
if object_id('[ta]') is not null drop table [ta]
create table [ta]([颜色] varchar(2),[款式] varchar(4),[批次] varchar(3))
insert [ta]
select '红','CT-1','1st' union all
select '红','CT-1','2nd' union all
select '红','CT-1','3rd' union all
select '蓝','CT-1','1st' union all
select '蓝','CT-1','2nd' union all
select '红','CT-2','1st' union all
select '白','CT-2','1st' union all
select '白','CT-2','2nd'
--------------开始查询--------------------------
SELECT * FROM ta T WHERE NOT EXISTS(SELECT 1 FROM ta WHERE [颜色]=T.[颜色] AND [款式]=T.[款式] AND [批次]>T.[批次])
----------------结果----------------------------
/*
颜色 款式 批次
---- ---- ----
红 CT-1 3rd
蓝 CT-1 2nd
红 CT-2 1st
白 CT-2 2nd
*/
create TABLE tb([颜色] NVARCHAR(1), [款式] VARCHAR(4), [批次] VARCHAR(3))
INSERT TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'SELECT *
FROM TB AS T
WHERE [批次] in (SELECT max([批次]) FROM TB WHERE [颜色]=T.[颜色] AND [款式]=T.[款式] )
order by [款式]
--颜色 款式 批次
------ ---- ----
--蓝 CT-1 2nd
--红 CT-1 3rd
--白 CT-2 2nd
--红 CT-2 1st
DECLARE @TB TABLE([颜色] NVARCHAR(1), [款式] VARCHAR(4), [批次] VARCHAR(3))
INSERT @TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'select * from @TBselect [颜色], [款式],[批次] from (select [颜色], [款式],[批次],row_number() over(partition by [颜色],[款式] order by [批次] desc) ord from @TB) m where ord=1
insert into @表 select '红','CT-1','1st'
union all select '红','CT-1','2nd'
union all select '红','CT-1','3rd'
union all select '蓝','CT-1','1st'
union all select '蓝','CT-1','2nd'
union all select '红','CT-2','1st'
union all select '白','CT-2','1st'
union all select '白','CT-2','1nd'
select * from @表 a where 批次 = (select MAX(批次) from @表 where a.颜色=颜色 and a.款式=款式 )
order by 款式蓝 CT-1 2nd
红 CT-1 3rd
白 CT-2 1st
红 CT-2 1st(4 行受影响)
declare @表 table (颜色 nvarchar(10),款式 nvarchar(10),批次 nvarchar(10))
insert into @表 select '红','CT-1','1st'
union all select '红','CT-1','2nd'
union all select '红','CT-1','3rd'
union all select '蓝','CT-1','1st'
union all select '蓝','CT-1','2nd'
union all select '红','CT-2','1st'
union all select '白','CT-2','1st'
union all select '白','CT-2','2nd'
select * from @表 a where 批次 = (select MAX(批次) from @表 where a.颜色=颜色 and a.款式=款式 )
order by 款式
---------- ---------- ----------
蓝 CT-1 2nd
红 CT-1 3rd
白 CT-2 2nd
红 CT-2 1st(4 行受影响)
INSERT @TB
SELECT N'红', 'CT-1', '1st' UNION ALL
SELECT N'红', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-1', '3rd' UNION ALL
SELECT N'蓝', 'CT-1', '1st' UNION ALL
SELECT N'蓝', 'CT-1', '2nd' UNION ALL
SELECT N'红', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '1st' UNION ALL
SELECT N'白', 'CT-2', '2nd'
select * from @TB B where not exists(select * from @TB where [颜色]=B.[颜色] and [款式]=B.[款式] and substring([批次],1,1)>substring(B.[批次],1,1))颜色 款式 批次
---- ---- ----
红 CT-1 3rd
蓝 CT-1 2nd
红 CT-2 1st
白 CT-2 2nd(4 行受影响)