Re: Selecting a random row

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От Kari Lavikka
Тема Re: Selecting a random row
Дата
Msg-id Pine.HPX.4.51.0411041526160.3138@purple.bdb.fi
обсуждение исходный текст
Ответ на Re: Selecting a random row  (Holger Klawitter <lists@klawitter.de>)
Ответы Re: Selecting a random row  (Csaba Nagy <nagy@ecircle-ag.com>)
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Works but is too slooow. Shuffling whole table and selecting the first
row is not the way to go in this case.

 Limit  (cost=5340.74..5340.74 rows=1 width=4)
   ->  Sort  (cost=5340.74..5440.70 rows=39986 width=4)
         Sort Key: random()
         ->  Seq Scan on users  (cost=0.00..2284.37 rows=39986 width=4)
               Filter: (status = 'a'::bpchar)

    |\__/|
    ( oo )    Kari Lavikka - tuner@bdb.fi
__ooO(  )Ooo_______ _____ ___ _ _  _   _    _      _                  _
      ""

On Thu, 4 Nov 2004, Holger Klawitter wrote:

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> On Thursday 04 November 2004 12:36, Kari Lavikka wrote:
> > Is there any explanation for this strange behavior or are there better
> > ways to select a random row?
>
> How about
>
>     SELECT ...whatever... ORDER BY random() LIMIT 1;
>
> Mit freundlichem Gruß / With kind regards
>     Holger Klawitter
> - --
> lists <at> klawitter <dot> de
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