Re: ROW_NUMBER alias

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От Robins
Тема Re: ROW_NUMBER alias
Дата
Msg-id 36af4bed0705061903y711ceb53v79ed176d5f849509@mail.gmail.com
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Ответ на Re: ROW_NUMBER alias  (Stefan Becker <pgsql@yukonho.de>)
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Hi Stefan,

Well that was just an example. That table had a primary key on (id, date). By bad then, coz I guess I should have clarified that earlier.

But what I meant from the example was that it is trivial for the parser to automatically put an enveloping SELECT to add a ROW_NUMBER() field to any user given query.

Regards,
Robins Tharakan

On 5/7/07, Stefan Becker <pgsql@yukonho.de > wrote:
I might be told off by some better SQL-User here on the list -
still here is my 2 Cents worth....

> I needed ROW_NUMBER() in PostGresql and I did find the 'temporary sequence'
> method as a workaround and i think it at least gets the job done relatively

you use:

>     CREATE TEMP SEQUENCE rownum;
>     SELECT nextval('rownum') AS row_number , t.a, t.b, t.c
>     FROM (
>         SELECT a, b, c
>         FROM table
>         WHERE table_id  = 973
>         ORDER BY record_date
>     ) t;

Doesn't this just return the 973th single record for the current
sequence order in your table?

I believe:
SELECT a, b, c FROM table
offset 973 limit 1

will accomplish the same result.


Stefan

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