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) */
declare @tb table (f1 varchar(20),f2 varchar(20)) insert into @tb select 'a','张1' insert into @tb select 'a','张1' insert into @tb select 'a','王1' insert into @tb select 'b','张3' insert into @tb select 'c','李4' insert into @tb select 'b','张3' select f1,count(distinct f2) as con from @tb group by f1f1 con a 2 b 1 c 1
--以上處理 select F1,count(distinct f2) from t group by F1
或
distinct
/******************************************************************************************************************************************************
Num、Name相同的重复值记录,只保留一条整理人:中国风(Roy)日期:2008.06.06
******************************************************************************************************************************************************/--> --> (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 @tb select 'a','张1'
insert into @tb select 'a','张1'
insert into @tb select 'a','王1'
insert into @tb select 'b','张3'
insert into @tb select 'c','李4'
insert into @tb select 'b','张3'
select f1,count(distinct f2) as con
from @tb
group by f1f1 con
a 2
b 1
c 1
select F1,count(distinct f2) from t group by F1