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)
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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