pg.ddx.io  pgsql-sql@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Bryce Nesbitt <bryce1@obviously.com>
To: pgsql-sql@postgresql.org
Subject: Can function results be used in WHERE?
Date: Mon, 10 Jul 2006 10:50:46 -0700
Message-ID: <44B29376.2030107@obviously.com> (raw)

I have a function, the results of which seem to apply to ORDER BY and
HAVING, but not to WHERE.  Is this expected?



-- Return distance in some mystery units (TODO: convert to miles or
kilometers)
CREATE FUNCTION calculate_distance(double precision, double precision,
double precision, double precision) RETURNS double precision
    AS '
BEGIN
    RETURN (3963 * acos( sin($1/57.2958) * sin($3/57.2958) +
cos($1/57.2958) * cos($3/57.2958) * cos($4/57.2958 - $2/57.2958) ));
END;
'
    LANGUAGE plpgsql;



demo=# select
pod_code,lat,lon,calculate_distance(lat,lon,37.789629,-122.422082) from
eg_pod where 4 > 5::double precision order by 4 limit 10;
 pod_code |    lat    |     lon     | calculate_distance
----------+-----------+-------------+--------------------
       44 |         0 |           0 |                  0
       45 |         0 |           0 |                  0
       69 | 37.789629 | -122.422082 |                  0
       51 | 37.788166 | -122.421488 |  0.106273303754946
       71 | 37.794228 | -122.421382 |  0.320393524437476
       73 | 37.787878 | -122.411644 |  0.583267064983836
       37 | 37.791736 | -122.411604 |  0.590977027054446
       46 | 37.784929 | -122.412782 |  0.603416307249032
       50 | 37.780329 | -122.418482 |  0.672685350683496
       30 | 37.780419 | -122.417764 |  0.679355355047995
(10 rows)

sdemo=# select
pod_code,lat,lon,calculate_distance(lat,lon,37.789629,-122.422082) from
eg_pod having calculate_distance(lat,lon,37.789629,-122.422082) > 5
order by 4;
 pod_code |    lat    |     lon     | calculate_distance
----------+-----------+-------------+--------------------
       21 | 37.710581 | -122.468864 |   6.03655070159813
       77 | 37.805427 |  -122.29528 |   7.01595024232628
       29 | 37.802684 | -122.275976 |    8.0364304687727
       12 | 37.806133 | -122.273827 |   8.18282157050301
       23 | 37.797327 |  -122.26598 |   8.54878571904839
       57 | 37.829592 | -122.266347 |   8.94791199923289
       35 | 37.809327 |  -122.25448 |   9.26077996779577
       47 | 37.851957 | -122.270376 |   9.34292370436932



demo=# select version();
                                                  version
-----------------------------------------------------------------------------------------------------------
 PostgreSQL 7.4.12 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.2.3
20030502 (Red Hat Linux 3.2.3-20)
(1 row)


-- 
----
Visit http://www.obviously.com/




view thread (10+ messages)  latest in thread

Message-ID: <44B29376.2030107@obviously.com>
Permalink:  ../44B29376.2030107@obviously.com/
Also on:    postgresql.org/message-id/44B29376.2030107@obviously.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-sql@postgresql.org
  Cc: bryce1@obviously.com
  Subject: Re: Can function results be used in WHERE?
  In-Reply-To: <44B29376.2030107@obviously.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox