Date: Tue, 3 Oct 2006 23:11:50 -0500
From: Bruno Wolff III <bruno@wolff.to>
To: paallen@attglobal.net
Cc: pgsql-sql@postgresql.org
Subject: Re: Fw: How to FindNearest
Message-ID: <20061004041150.GA30862@wolff.to>
Mail-Followup-To: Bruno Wolff III <bruno@wolff.to>, paallen@attglobal.net,
	pgsql-sql@postgresql.org
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On Tue, Oct 03, 2006 at 17:35:55 +0000,
  paallen@attglobal.net wrote:
> 
> My function will take all the above info about the hole and down_hole_survey tables, and sample.hole_id and sample.depth_meters and will calculate the coordinates.  I need to put these coordinates into sample.x , sample.y and sample.z .
> 
> What I used to do was have one function that would return 3 values (x,y,z).  Then create 3 more functions that would call call the main function and pull out the 3 values seperately to update the 3 seperate columns.  It works fine but I have to call the main function 3 times which produces a slow performance.
> 
> I hope that I explained it better this time.

If they are in the same table you can update all there in the same
update statement using syntax something like the following:
UPDATE sample SET x=(some expression), y=(some expression), z=(some expression)
  WHERE some condition;

Probably the simplest place to start is having your function do the update
rather than return the three values.
I think in 8.2 there will be an easier way to use the result of a function that
returns a row to update multiple columns in an update statement. (That
doesn't resu;t in calling the function three times.)