Re: "People near me" query

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: bas(at)scheffers(dot)net
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: "People near me" query
Date: 2004-03-19 15:01:57
Message-ID: 24093.1079708517@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

"Bas Scheffers" <bas(at)scheffers(dot)net> writes:
> Once you have that, the rest is easy. create a column of the type "point"
> and store the grid coordinates in there. The just use the "contains"
> operator (~) in a query.
> (http://www.postgresql.org/docs/7.4/static/functions-geometry.html)

> Example:
> My coordinates are 523857,175349. So to find anyone living within 10KM of
> me, I just do "select * from people where '((523857,175349),10000)' ~
> location"

> Unfortunately, Postgres doesn't know how to index this.

You can index such queries using rtree indexes. There was a discussion
of this with a full example just a couple weeks ago:
http://archives.postgresql.org/pgsql-novice/2004-03/msg00070.php

It's likely that PostGIS provides an even better solution, but I haven't
used it.

regards, tom lane

In response to

Browse pgsql-general by date

  From Date Subject
Next Message Carmen Gloria Sepulveda Dedes 2004-03-19 15:13:12 7.4.2 on Solaris 9 - Error
Previous Message Stephan Szabo 2004-03-19 15:00:59 Re: self referenced table ?