Re: conditional aggregates

From: Marcin Krawczyk <jankes(dot)mk(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: conditional aggregates
Date: 2010-12-08 13:19:49
Message-ID: AANLkTimkN1DZS44p_47MJJ85aWmvQybxh3m32=eHuxsE@mail.gmail.com
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Yeah I know but I'm having problems creating sfunc fuction for the
aggregate.

regards
mk

2010/12/8 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>

> Hello
>
> use a CASE statement
>
> http://www.postgresql.org/docs/7.4/static/functions-conditional.html
>
> Regards
>
> Pavel Stehule
>
> 2010/12/8 Marcin Krawczyk <jankes(dot)mk(at)gmail(dot)com>:
> > Hi list,
> > Can anyone advise me on creating an aggregate that would take additional
> > parameter as a condition ? For example, say I have a table like this
> > id;value
> > 1;45
> > 2;13
> > 3;0
> > 4;90
> > I'd like to do something like this
> > SELECT min_some_cond_aggregate(value,0) FROM table
> > to get the minimal value from table greater than 0, in this case 13.
> > I can't do SELECT min(value) FROM table WHERE value > 0 as this will mess
> my
> > other computations. My current solution involves a function operating on
> the
> > output of array_accum from the docs, but I'm looking for more elegant
> > solution.
> > Is this possible at all ? I'm running 8.1.
> >
> > regards
> > mk
> >
>

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