Re: Getting a random row

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От
Thom Brown
Тема
Re: Getting a random row
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bddc86150910132358g7f1af750qb90ab0d396c22f5c@mail.gmail.com
Ответ на
Re: Getting a random row (Scott Marlowe)
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Getting a random row Shaul Dar <shauldar@gmail.com>
Re: Getting a random row Grzegorz Jaśkiewicz <gryzman@gmail.com>
Re: Getting a random row Shaul Dar <shauldar@gmail.com>
Re: Getting a random row Grzegorz Jaśkiewicz <gryzman@gmail.com>
Re: Getting a random row bricklen <bricklen@gmail.com>
Re: Getting a random row Robert Haas <robertmhaas@gmail.com>
Re: Getting a random row Michael Glaesemann <grzm@seespotcode.net>
Re: Getting a random row Shaul Dar <shauldar@gmail.com>
Re: Getting a random row Scott Marlowe <scott.marlowe@gmail.com>
Re: Getting a random row Thom Brown <thombrown@gmail.com>
Re: Getting a random row Pavel Stehule <pavel.stehule@gmail.com>
Re: Getting a random row Scott Marlowe <scott.marlowe@gmail.com>
Re: Getting a random row Віталій Тимчишин <tivv00@gmail.com>
Re: Getting a random row Thomas Kellerer <spam_eater@gmx.net>
2009/10/14 Scott Marlowe :
>
> If what you're trying to do is emulate a real world app which randomly
> grabs rows, then you want to setup something ahead of time that has a
> pseudo random order and not rely on using anything like order by
> random() limit 1 or anything like that.  Easiest way is to do
> something like:
>
> select id into randomizer from maintable order by random();
>
> then use a cursor to fetch from the table to get "random" rows from
> the real table.
>
>

Why not just do something like:

SELECT thisfield, thatfield
FROM my_table
WHERE thisfield IS NOT NULL
ORDER BY RANDOM()
LIMIT 1;

Thom
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