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Message-ID: <7539aebb0702231129s48399f26r8881c6eff81b0708@mail.gmail.com>
Date: Fri, 23 Feb 2007 14:29:13 -0500
From: Sumeet <asumeet@gmail.com>
To: pgsql-sql@postgresql.org
Subject: selecting random row values in postgres
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Hi all,

I'm trying to write  a query to select random values from a set of 'GROUP
BY'
....see the scenario below to understand the problem here (the actual
problem cannot be discussed here so i'm taking an example scenario)

Assume there is a table

id | name | year_of_birth

query: I want  to select for each year_of_birth a random name.

--> so i do a group by year_of_birth, now i have a set of names, is there
any function to select just one name from these set of names.
The current approach i'm using to solve this problem is

1) getting these names in a single string using a custom function
'group_concat'
2) Convert the single string into an array
3) use postgresql random function to generate  a random number
4) us the random number to select a element from the array previously
created.

The solution is there but it's kinda hack, is there any other better way of
solving this problem.


Thanks,
Sumeet

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Hi all,<br><br>I&#39;m trying to write&nbsp; a query to select random values from a set of &#39;GROUP BY&#39;<br>....see the scenario below to understand the problem here (the actual problem cannot be discussed here so i&#39;m taking an example scenario)
<br><br>Assume there is a table<br><br>id | name | year_of_birth<br><br>query: I want&nbsp; to select for each year_of_birth a random name.<br><br>--&gt; so i do a group by year_of_birth, now i have a set of names, is there&nbsp; any function to select just one name from these set of names.
<br>The current approach i&#39;m using to solve this problem is <br><br>1) getting these names in a single string using a custom function &#39;group_concat&#39;<br>2) Convert the single string into an array <br>3) use postgresql random function to generate&nbsp; a random number 
<br>4) us the random number to select a element from the array previously created.<br><br clear="all">The solution is there but it&#39;s kinda hack, is there any other better way of solving this problem.<br><br><br>Thanks,
<br>Sumeet

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