Re: Getting the output of a function used in a where clause

Boy I sure thought that would work... I received the following from postgres:

ERROR: Attribute "distance" not found.

Started looking into gist.... Looks complex.

Any other ideas?

-----Original Message-----
From: PFC [mailto:lists(at)boutiquenumerique(dot)com]
Sent: Monday, April 11, 2005 1:51 AM
To: Bill Lawrence; pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] Getting the output of a function used in a where clause

try:

SELECT zipcode, zipdist($lat1d,$lon1d,lat,long) as distance from zipcodes
where distance <= $dist;";

OR you could use a gist index with a geometric datatype to get it a lot
faster.

On Sat, 09 Apr 2005 03:43:39 +0200, Bill Lawrence <bill(dot)lawrence(at)cox(dot)net>
wrote:

> HI,
>
> I'm a newbie so please bear with me. I have a function defined (got it
> from
> one of your threads... thanks Joe Conway) which calculates the distance
> between 2 zip code centeroids (in lat,long). This thing works great.
> However, I want to sort my results by distance without incurring the
> additional burden of executing the function twice. A simplified version
> of
> my current SQL (written in a perl cgi) that returns a set of zip codes
> within a given radius is:
>
>
> What I want to write is something like:
>
> $sql = "SELECT zipcode, distance from zipcodes where distance <= $dist
> order
> by distance;";
>
> But I don't the magic SQL phrase to populate the distance variable using
> my
> nifty function. Do I need to create an output type for distance?
>
> Thanks in advance!
>
> Bill
>
>
>