【转帖】SQL Oracle删除重复记录

1.Oracle删除重复记录.

删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录.

delete from people
where peopleId  in (select  peopleId  from people  group  by  peopleId   having  count(peopleId) > 1)
and rowid not in (select min(rowid) from  people  group by peopleId  having count(peopleId )>1)

删除表中多余的重复记录（多个字段），只留有rowid最小的记录
delete from vitae a
where (a.peopleId,a.seq) in  (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

================================

此方法可以适用于sql ,oracle

declare @max integer,@id integer

declare cur_rows cursor local for select 主字段,count(*) from 表名 group by 主字段 having count(*) >； 1

open cur_rows

fetch cur_rows into @id,@max

while @@fetch_status=0

begin

select @max = @max -1

set rowcount @max

delete from 表名 where 主字段 = @id

/*

DECLARE @count INT
SELECT @count = COUNT(*) FROM [table1] WHERE [column1] = 1
DELETE TOP (@count-1) FROM [table1] WHERE [column1] = 1  这个top后面一定要有括号

*/

fetch cur_rows into @id,@max

end

close cur_rows

set rowcount 0

 =======================================

select distinct * into #Tmp from tableName

drop table tableName

select * into tableName from #Tmp

drop table #Tmp

select identity(int,1,1) as autoID, * into #Tmp from tableName

select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID

select * from #Tmp where autoID in(select autoID from #tmp2)

=======================================

 select identity(int,1,1) as id ,name,state into #tempTable from a
delete from a
delete from #tempTable
where id not in
(
 select min(id) from #tempTable group by name
)

insert into a( name,state)
select name,state from #tempTable

drop table #tempTable

本文来自CSDN博客，出处：http://blog.csdn.net/xiaohutushen/archive/2008/03/20/2199947.aspx