现有一个表
编号 商品 单位 日期
01 11 aa 2008-09-30
02 11 bb 2008-10-05
03 11 cc 2008-10-07
04 12 dd 2008-09-30
05 13 aa 2008-09-30
06 14 aa 2008-09-30
07 14 ee 2008-10-02
08 15 aa 2008-09-30
09 15 aa 2008-10-03
10 15 aa 2008-10-05
需要得到的结果
编号 商品 单位 日期
03 11 cc 2008-10-07
04 12 dd 2008-09-30
05 13 aa 2008-09-30
07 14 ee 2008-10-02
10 15 aa 2008-10-05
此结果是相同商品的最后一次的供货单位,请教
编号 商品 单位 日期
01 11 aa 2008-09-30
02 11 bb 2008-10-05
03 11 cc 2008-10-07
04 12 dd 2008-09-30
05 13 aa 2008-09-30
06 14 aa 2008-09-30
07 14 ee 2008-10-02
08 15 aa 2008-09-30
09 15 aa 2008-10-03
10 15 aa 2008-10-05
需要得到的结果
编号 商品 单位 日期
03 11 cc 2008-10-07
04 12 dd 2008-09-30
05 13 aa 2008-09-30
07 14 ee 2008-10-02
10 15 aa 2008-10-05
此结果是相同商品的最后一次的供货单位,请教
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declare @s table (编号 varchar(2),商品 int,单位 varchar(2),日期 datetime)
insert into @s
select '01',11,'aa','2008-09-30' union all
select '02',11,'bb','2008-10-05' union all
select '03',11,'cc','2008-10-07' union all
select '04',12,'dd','2008-09-30' union all
select '05',13,'aa','2008-09-30' union all
select '06',14,'aa','2008-09-30' union all
select '07',14,'ee','2008-10-02' union all
select '08',15,'aa','2008-09-30' union all
select '09',15,'aa','2008-10-03' union all
select '10',15,'aa','2008-10-05'select * from @s a where not exists(select 1 from @s where 商品=a.商品 and 日期>a.日期)
--> 测试数据: @s
declare @s table (编号 varchar(2),商品 int,单位 varchar(2),日期 datetime)
insert into @s
select '01',11,'aa','2008-09-30' union all
select '02',11,'bb','2008-10-05' union all
select '03',11,'cc','2008-10-07' union all
select '04',12,'dd','2008-09-30' union all
select '05',13,'aa','2008-09-30' union all
select '06',14,'aa','2008-09-30' union all
select '07',14,'ee','2008-10-02' union all
select '08',15,'aa','2008-09-30' union all
select '09',15,'aa','2008-10-03' union all
select '10',15,'aa','2008-10-05'
--方法1:
select * from @s a where not exists(select 1 from @s where 商品=a.商品 and 日期>a.日期)--方法2:
select * from @s a where(select count(日期) from @s where 商品=a.商品 and 日期>=a.日期)=1--方法3:
select a.* from @s a,(select 商品,日期=max(日期) from @s group by 商品)b
where a.商品=b.商品 and a.日期=b.日期--等等
select * from @s a where not exists(select 1 from @s where 商品=a.商品 and 日期>a.日期)
推荐使用
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)
*/
insert into sss
select '01',11,'aa','2008-09-30' union all
select '02',11,'bb','2008-10-05' union all
select '03',11,'cc','2008-10-07' union all
select '04',12,'dd','2008-09-30' union all
select '05',13,'aa','2008-09-30' union all
select '06',14,'aa','2008-09-30' union all
select '07',14,'ee','2008-10-02' union all
select '08',15,'aa','2008-09-30' union all
select '09',15,'aa','2008-10-03' union all
select '10',15,'aa','2008-10-05'select * from sss s where not Exists (select * from sss where Sdate>s.Sdate and s.ProductID=ProductID)
Set Nocount On
declare @1 table([编号] nvarchar(2),[商品] int,[单位] nvarchar(2),[日期] Datetime)
Insert @1
select N'01',11,N'aa','2008-09-30' union all
select N'02',11,N'bb','2008-10-05' union all
select N'03',11,N'cc','2008-10-07' union all
select N'04',12,N'dd','2008-09-30' union all
select N'05',13,N'aa','2008-09-30' union all
select N'06',14,N'aa','2008-09-30' union all
select N'07',14,N'ee','2008-10-02' union all
select N'08',15,N'aa','2008-09-30' union all
select N'09',15,N'aa','2008-10-03' union all
select N'10',15,N'aa','2008-10-05'
Select * from @1 a Where [编号]=(Select Max([编号]) From @1 Where [商品]=a.[商品] ) Order By [编号]/*
编号 商品 单位 日期
---- ----------- ---- -----------------------
03 11 cc 2008-10-07 00:00:00.000
04 12 dd 2008-09-30 00:00:00.000
05 13 aa 2008-09-30 00:00:00.000
07 14 ee 2008-10-02 00:00:00.000
10 15 aa 2008-10-05 00:00:00.000
*/
--设表名为Aselect A.*
from A,(select 商品,max(日期) as 日期 from A group by 商品) b
where a.商品=b.商品 and a.日期=b.日期