oracle查询重复数据和删除重复记录示例分享

   select 
     from User u
     where u.user_name in (select u.user_name 
                 from User u
                group by u.user_name  having count() > 1)

id customer PhoneNo 
001 张三 777777 
002 李四 444444 
003 王五 555555 
004 张三 777777 
005 张三 777777 
006 王五 555555 
如何写一个sql语句将TableA变成如下 
001 张三 777777 
002 李四 444444 
003 王五 555555

create table TableA ( id varchar(3),customer varchar(5),PhoneNo varchar(6)) 
insert into TableA select '001','张三','777777' 
union all select '002','李四','444444' 
union all select '003','王五','555555' 
union all select '004','张三','777777' 
union all select '005','张三','777777' 
union all select '006','王五','555555'

delete TableA from TableA Twhere

exists( 
select 1fromtablea where customer=T.customer and phoneno=T.phoneno 
andid < tt.id
)

delete 表名 from 表名 as Twhere

exists( 
select 1from表名 where 字段A=T.字段A and 字段B=T.字段B,(....) 
and自增列 < T.自增列
)

select  from people 
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) 

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)

select  from vitae a 
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count() > 1) 

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) 

select  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) 

Select Name,Count() From A Group By Name Having Count() > 1 

Select Name,sex,Count() From A Group By Name,sex Having Count() > 1 

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 
fetch cur_rows into @id,@max 
end 
close cur_rows 

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  from tablename where id in ( 
select id from tablename 
group by id 
having count(id) > 1 
)