Wednesday, March 28, 2012

Finding duplicate based on records in same table

I need a help with a sql...
Is there a way to find a duplicate value based on different records
inside the same table?
I got a scenario, where I'm getting same ID with different date...
I need to get rid of one with earlier date...
Thanks in advance...paulcasso@.gmail.com,
- Can you be more explicit and post some DDl, sample data and expected resul
t?
- Which version are you using 2000 or 2005?
;with cte
as
(
select
[date], [id],
row_number () over(partition by [id] order by [date] DESC) as rn
from
dbo.t1
)
delete cte
where rn > 1;
AMB
"paulcasso@.gmail.com" wrote:

> I need a help with a sql...
> Is there a way to find a duplicate value based on different records
> inside the same table?
> I got a scenario, where I'm getting same ID with different date...
> I need to get rid of one with earlier date...
> Thanks in advance...
>|||Take a look at this example:
--SQL Begins--
use tempdb
go
create table #tablename(
id_field int not null,
dt_field datetime not null
)
go
insert #tablename values(1, '1/1/2007')
insert #tablename values(2, '1/2/2007')
insert #tablename values(2, '1/3/2007')
insert #tablename values(3, '1/4/2007')
insert #tablename values(2, '1/5/2007')
insert #tablename values(3, '1/6/2007')
insert #tablename values(1, '1/7/2007')
go
-- deletes all but the most recent record for each id
delete a
from #tablename a
left join ( select id_field, max(dt_field) dt
from #tablename
group by id_field) b
on a.id_field = b.id_field and a.dt_field = b.dt
where b.id_field is null
go
select * from #tablename
go
drop table #tablename
go
--SQL Ends--
On Apr 11, 2:20 pm, "paulca...@.gmail.com" <paulca...@.gmail.com> wrote:
> I need a help with a sql...
> Is there a way to find a duplicate value based on different records
> inside the same table?
> I got a scenario, where I'm getting same ID with different date...
> I need to get rid of one with earlier date...
> Thanks in advance...|||Thank you for your help.,
but where does value dt coming from?
...on a.id_field = b.id_field and a.dt_field = b.dt ...|||On Apr 11, 4:21 pm, "paulca...@.gmail.com" <paulca...@.gmail.com> wrote:
> Thank you for your help.,
> but where does value dt coming from?
> ...on a.id_field = b.id_field and a.dt_field = b.dt ...

>From a previous post:
left join ( select id_field, max(dt_field) dt
dt is an alias for max(dt_field)
Cheers,
Jason Lepack|||Hi
[url]http://dimantdatabasesolutions.blogspot.com/2007/02/dealing-with-duplicates.html[/
url]
<paulcasso@.gmail.com> wrote in message
news:1176315620.878773.240790@.y5g2000hsa.googlegroups.com...
>I need a help with a sql...
> Is there a way to find a duplicate value based on different records
> inside the same table?
> I got a scenario, where I'm getting same ID with different date...
> I need to get rid of one with earlier date...
> Thanks in advance...
>

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