我有个表docketlist,结构如下:
docketno technician docketdate
0900102 001 2011-07-01
0900103 002 2011-07-02
0900105 006 2011-07-18
0900102 001 2011-07-01
0900103 003 2011-07-06
要求:表里面有完全重复的数据,只保留一条,部分重合的数据全部删除,这个sql语句怎么写?
最后结果应该是这样的
docketno technician docketdate
0900102 001 2011-07-01
0900105 006 2011-07-18
docketno technician docketdate
0900102 001 2011-07-01
0900103 002 2011-07-02
0900105 006 2011-07-18
0900102 001 2011-07-01
0900103 003 2011-07-06
要求:表里面有完全重复的数据,只保留一条,部分重合的数据全部删除,这个sql语句怎么写?
最后结果应该是这样的
docketno technician docketdate
0900102 001 2011-07-01
0900105 006 2011-07-18
from (select *,row=row_number()over(partition by docketno,technician order by docketno ) from t)a
where row>1
?
DECLARE @T TABLE(ID int)
INSERT @T SELECT 1
INSERT @T SELECT 1
INSERT @T SELECT 1DELETE t
FROM
(SELECT *,row=ROW_NUMBER()OVER( PARTITION BY ID ORDER BY ID) FROM @T)t
WHERE row>1SELECT * FROM @T/*
1
*/
go
--> -->
if not object_id(N'docketlist') is null
drop table docketlist
Go
Create table docketlist([docketno] nvarchar(7),[technician] nvarchar(3),[docketdate] Datetime)
Insert docketlist
select N'0900102',N'001','2011-07-01' union all
select N'0900103',N'002','2011-07-02' union all
select N'0900105',N'006','2011-07-18' union all
select N'0900102',N'001','2011-07-01' union all
select N'0900103',N'003','2011-07-06'
Go
delete a
from (select *,row=row_number()over(partition by docketno order by [docketdate] ) from docketlist)a
where row>1SELECT * FROM docketlist
/*
docketno technician docketdate
0900102 001 2011-07-01 00:00:00.000
0900103 002 2011-07-02 00:00:00.000
0900105 006 2011-07-18 00:00:00.000
*/
--> --> (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)
*/
go
--> -->
if not object_id(N'docketlist') is null
drop table docketlist
Go
Create table docketlist([docketno] nvarchar(7),[technician] nvarchar(3),[docketdate] Datetime)
Insert docketlist
select N'0900102',N'001','2011-07-01' union all
select N'0900103',N'002','2011-07-02' union all
select N'0900105',N'006','2011-07-18' union all
select N'0900102',N'001','2011-07-01' union all
select N'0900103',N'003','2011-07-06'
Go
DELETE a FROM docketlist AS a INNER JOIN docketlist AS b ON a.[docketno]=b.[docketno] AND a.[technician]<>b.[technician]
WHERE NOT EXISTS(SELECT 1 FROM docketlist WHERE [docketno]=a.[docketno] AND [technician]=a.[technician] AND [docketdate]=a.[docketdate] HAVING COUNT(1)>1)delete a
from (select *,row=row_number()over(partition by docketno order by [docketdate] ) from docketlist)a
where row>1SELECT * FROM docketlist
/*
docketno technician docketdate
0900102 001 2011-07-01 00:00:00.000
0900105 006 2011-07-18 00:00:00.000
*/
DELETE a FROM docketlist AS a INNER JOIN docketlist AS b ON a.[docketno]=b.[docketno] AND a.[technician]<>b.[technician]delete a
from (select *,row=row_number()over(partition by docketno order by [docketdate] ) from docketlist)a
where row>1SELECT * FROM docketlist
create table docketlist(docketno varchar(10),technician varchar(10),docketdate datetime)
insert into docketlist select '0900102','001','2011-07-01'
insert into docketlist select '0900103','002','2011-07-02'
insert into docketlist select '0900105','006','2011-07-18'
insert into docketlist select '0900102','001','2011-07-01'
insert into docketlist select '0900103','003','2011-07-06'
go
select distinct * into # from docketlist
drop table docketlist
select distinct * into docketlist from #
select * from docketlist
/*
docketno technician docketdate
---------- ---------- -----------------------
0900102 001 2011-07-01 00:00:00.000
0900103 002 2011-07-02 00:00:00.000
0900103 003 2011-07-06 00:00:00.000
0900105 006 2011-07-18 00:00:00.000(4 行受影响)*/
go
drop table docketlist,#
from (select *,row=row_number()over(partition by docketno order by [docketdate] ) from docketlist)a
where row>1这个好.