Re: How to delete completely duplicate rows

Hi,
 
I want to delete duplicates in my table. I've dropped the unique constraint to insert my data.
My id value is a hash calculated witch the values of the two other columns.
So I want to delete all columns, which are indentical, but keeping one.
 
DELETE FROM table t1 USING table t2 WHERE t1.id = t2.id AND t1.ctid > t2.ctid

But the oids aren't unique enough.
What else could I do?

Janek

With C as (
Select row_number() over partition by (list, all, columns, here order by
oid) as rn
)
Delete
From C
Where rn > 1;
On Jan 1, 2014 7:15 AM, "Janek Sendrowski" <janek12(at)web(dot)de> wrote:

> Hi,
>
> I want to delete duplicates in my table. I've dropped the unique
> constraint to insert my data.
> My id value is a hash calculated witch the values of the two other columns.
> So I want to delete all columns, which are indentical, but keeping one.
>
> DELETE FROM table t1 USING table t2 WHERE t1.id = t2.id AND t1.ctid >
> t2.ctid
>
> But the oids aren't unique enough.
> What else could I do?
>
> Janek
>
>
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On Wed, Jan 1, 2014 at 4:14 AM, Janek Sendrowski <janek12(at)web(dot)de> wrote:

> I want to delete duplicates in my table. I've dropped the unique
> constraint to insert my data.
> My id value is a hash calculated witch the values of the two other columns.
> So I want to delete all columns, which are indentical, but keeping one.
>
> DELETE FROM table t1 USING table t2 WHERE t1.id = t2.id AND t1.ctid >
> t2.ctid
>
> But the oids aren't unique enough.
> What else could I do?

http://postgres.cz/wiki/PostgreSQL_SQL_Tricks#Delete_duplicate_rows_with_window_analytic_functions
http://wiki.postgresql.org/wiki/Deleting_duplicates

Thanks!
It's working
 
Janek

On Thu, Jan 2, 2014 at 4:33 AM, Janek Sendrowski <janek12(at)web(dot)de> wrote:
> Thanks!
> It's working

you can do it without listing columns via:

select *, row_number() over(partition by c) from c;

emphasis on 'partition by c'.

merlin