相同元组删除的问题？？

[RogerWT]

一表中员组有如下相同数值：
字段
a
a
b
b
c
c
d
d
现想删除重复元组，只留下一个数值，怎么做？
我有如下两种方法：
1、用游标一个个的取出来在与下一行值比较应该可以，
2、新建个表，然后查处distinct值，然后插入其中应该可以，还有什么方法呢？
请指教，谢过了！

[xluzhong]

alter table tablename add id int identity(1,1)
go
select *
from tablename a
where exists(select 1 from tablename where col=a.col and id<a.id)
---
select *
from tablename
where id not in(select min(id) from tablename group by col)
go
alter tablename drop column id

[jackeychen0920]

delete from tablename where id in(select id from tablename a where
(select count(id) as Ts from tablename b where a.id=b.id)>1 )
删除表tablename里的字段ID重读记录

[jinjazz]

distinct是最好的

[wyb0026]

create table test (a char(10),b char(10))
insert test select 'a','1'
insert test select 'b','1'
insert test select 'b','1'
insert test select 'b','1'
insert test select 'a','1'
insert test select 'a','1'
insert test select 'c','1'
insert test select 'c','1'

select * into #t from test
group by a,b

truncate table test

insert into test select * from #t

select * from test

drop table #t
drop table test