数据库中删除重复记录

1，利用临时表来删除

 

A是原表，temp是临时表

 

select distinct *  into temp from A

 

delete from A

 

insert into A select * from temp

 

select * from A

 

 

2,利用自增字段

 

alter table A add columns_b int identity(1 ,1)

 

delete from A where columns_b not in(select max(columns_b) from A group by id,name....)

 

alter table A drop column columns_b