Re: Getting a random row

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От
Thomas Kellerer
Тема
Re: Getting a random row
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hb26d4$3kn$1@ger.gmane.org
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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>
Shaul Dar, 13.10.2009 17:17:
> Also PG does not have a concept of an auto-increment pseudo-column
> like Oracle's "rownum". Any suggestions?

Yes it does (at least 8.4)

SELECT row_number() over(), the_other_columns...
FROM your_table

So you could do something like:

SELECT * 
FROM (
  SELECT row_number() over() as rownum, 
         the_other_columns...
  FROM your_table
) t 
WHERE t.rownum = a_random_integer_value_lower_than_rowcount;

Thomas


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