From: | Andy Colson <andy(at)squeakycode(dot)net> |
---|---|
To: | Aaron Burnett <aburnett(at)bzzagent(dot)com>, PostgreSQL <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Some insight on the proper SQL would be appreciated |
Date: | 2010-06-08 17:56:07 |
Message-ID: | 4C0E8437.2040801@squeakycode.net |
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Lists: | pgsql-general |
On 6/8/2010 11:29 AM, Aaron Burnett wrote:
>
> Greetings,
>
> I hope this is the proper list for this, but I am a loss on how to achieve
> one particular set of results.
>
> I have a table which is a list of users who entered a contest. They can
> enter as many times as they want, but only 5 will count. So some users have
> one entry, some have as many as 15.
>
is it possible to add a new column: "isValid integer"
(or something like it, to signify which one's can and cannot be selected)
I was thinking of doing it in two steps, an update to set isValid, then
a select with just "isValid = 1". Not sure how hard the update would be
though.
Oh, wait, I'll bet a window function would be helpful... but you are on
8.2 so I dont think you have them.
I can think of a stored proc that might work, that ok?
Oh, another thought.. if we order it by username, signedup, and then did
something like:
where ... signedup > (select the 5th signedup from users ... )
not 100% how to do the subselect though. I can see min(signedup) or
max(signedup), but not sure how to get the 5th.
Not real helpful, sorry, just some random thoughts
-Andy
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