Thread: How to Make aggragate Function? Standard Deviation?

Hi all,

I am just starting to write functions in plpgsql.  I have made some
simple functions but now I need a standard deviation function.  The
documentation was not too clear so does anyone have any suggestion on
how to begin?  I can do this in plpgsql or do I need to do this in C?

thanks,

Phillip J. Allen
Consulting Geochemist/Geologist
Lima Peru
e-mail: paallen@attglobal.ent

What version of PostgreSQL are you using?  Version 7.1
has stddev() built right in (I don't believe it was
available in the 7.0 series, and I can guarantee it
wasn't in the 6.5 series).  I use it all of the time.

SELECT stddev(weight) FROM caseweights1;

Jason

--- "Phillip J. Allen" <paallen@attglobal.net> wrote:
> Hi all,
>
> I am just starting to write functions in plpgsql.  I
> have made some
> simple functions but now I need a standard deviation
> function.  The
> documentation was not too clear so does anyone have
> any suggestion on
> how to begin?  I can do this in plpgsql or do I need
> to do this in C?
>
> thanks,
>
> Phillip J. Allen
> Consulting Geochemist/Geologist
> Lima Peru
> e-mail: paallen@attglobal.ent
>
>
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> broadcast)---------------------------
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