To: "Bill Lawrence" <bill.lawrence@cox.net>, pgsql-sql@postgresql.org
Subject: Re: Getting the output of a function used in a where clause
References: <NEBBJBFOALCOMIDOAMHCCELJDAAA.bill.lawrence@cox.net>
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Date: Mon, 11 Apr 2005 10:51:28 +0200
From: PFC <lists@boutiquenumerique.com>
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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.lawrence@cox.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
>
>
>