表tb 就两字段 c_id,c_df
c_id c_df
1 90
2 85
1 90
2 85
3 80
2 85 把重复数据给删除掉
两列的重复都删除了
保留一条数据
c_id c_df
1 90
2 85
3 80
c_id c_df
1 90
2 85
1 90
2 85
3 80
2 85 把重复数据给删除掉
两列的重复都删除了
保留一条数据
c_id c_df
1 90
2 85
3 80
调试欢乐多
select distinct * into #tb from tbtruncate table tb
insert into tb
select * into from #tb
--> --> (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)
*/
select distinct * into #tb from tbtruncate table tbinsert into tb select * from #tb
create table tb
(
id int,
df int
)
insert into tb values(1,90)
insert into tb values(2,85)
insert into tb values(1,90)
insert into tb values(2,85)
insert into tb values(3,80)
insert into tb values(2,85)delete t from
(
select row_number() over (partition by id ,df order by id) num , id ,df
from tb
) t where num <> 1select * from tb
/*
id,df
1,90
2,85
3,80(3 行受影响)