From: | David Fetter <david(at)fetter(dot)org> |
---|---|
To: | artacus(at)comcast(dot)net |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Aggregate Function to return most common value for a column |
Date: | 2009-05-22 20:36:07 |
Message-ID: | 20090522203607.GA10465@fetter.org |
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Thread: | |
Lists: | pgsql-general |
On Fri, May 22, 2009 at 05:23:47PM +0000, artacus(at)comcast(dot)net wrote:
>
> On Fri, May 22, 2009 at 03:23:07PM +0000, artacus(at)comcast(dot)net wrote:
> > > I want to use an aggregate function that will return the most
> > > commonly occurring value in a column.
> >
> > It's actually dead simple in Postgres. No C either. You just need to
> > create an aggregate function. I wrote a most() aggregate a while
> > back that does exactly what you are asking for. Here, I'll add it to
> > my blog...
> >
> > http://scottrbailey.wordpress.com/2009/05/22/postgres-adding-custom-aggregates-most/
>
> > Such an aggregate should probably be called, "mode," that being the
> > probability/statistics name for the concept.
>
> Excellent observation Dave. Sometimes I can't see outside of the box I'm in. And at the time I was focusing on text so statistics was in another box. I've update post with final functions for mode(), median() and range().
Thanks! :)
Cheers,
David.
--
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