Thread: Bounds checking on an alias

Hi,

Removing the double single-quotes from the distance function fixed the
problem, thanks.  I've now encountered another problem...

I have the following (ugly) query:

SELECT DISTINCT tbl_restaurant.restaurant,
tbl_restaurant_location.postal_code, tbl_restaurant_location.latitude
AS latitude, tbl_restaurant_location.longitude AS longitude, distance
(49.24894, -122.90419, latitude, longitude) AS distance FROM
tbl_restaurant, tbl_restaurant_location, tbl_restaurant_cuisine_link
WHERE tbl_restaurant.restaurant_id =
tbl_restaurant_location.restaurant_id AND tbl_restaurant.restaurant_id
= tbl_restaurant_cuisine_link.restaurant_id AND
tbl_restaurant_cuisine_link.cuisine_id = 14 AND
tbl_restaurant.price_id = 1 AND tbl_restaurant_location.latitude IS
NOT NULL AND tbl_restaurant_location.latitude > 49.113804 AND
tbl_restaurant_location.latitude < 49.384075 AND
tbl_restaurant_location.longitude > -123.03932 AND
tbl_restaurant_location.longitude < -122.76906 AND distance <= 15.0
ORDER BY distance;

What I'm doing is selecting all restaurants of a particular cuisine
and within a particular price range.  Out of the restaurants that meet
those criteria I only want the ones within a certain range of my
location- in this case, 49.24894, -122.90419.  The way I narrow down
the search results is to select only those restaurants within certain
lat/lon points; basically, I'm selecting restaurants that fall in a
square region with my location in the middle.  Then, I'm applying my
distance formula to filter these results.  When I try and do a
"distance <= 15.0" I get:

ERROR:  Attribute 'distance' not found

If I remove that particular clause it works fine but my results aren't
as accurate as they need to be.  Any ideas?

Thanks,
Jamu.

-- 
Jamu Kakar (Developer)            Expressus Design Studio, Inc.
jkakar@expressus.com            708-1641 Lonsdale Avenue
V: (604) 988-6999            North Vancouver, BC, V7M 2J5

jkakar@expressus.com wrote:

> SELECT DISTINCT tbl_restaurant.restaurant,
> tbl_restaurant_location.postal_code, tbl_restaurant_location.latitude
> AS latitude, tbl_restaurant_location.longitude AS longitude, distance
> (49.24894, -122.90419, latitude, longitude) AS distance FROM
> tbl_restaurant, tbl_restaurant_location, tbl_restaurant_cuisine_link
> WHERE tbl_restaurant.restaurant_id =
> tbl_restaurant_location.restaurant_id AND tbl_restaurant.restaurant_id
> = tbl_restaurant_cuisine_link.restaurant_id AND
> tbl_restaurant_cuisine_link.cuisine_id = 14 AND
> tbl_restaurant.price_id = 1 AND tbl_restaurant_location.latitude IS
> NOT NULL AND tbl_restaurant_location.latitude > 49.113804 AND
> tbl_restaurant_location.latitude < 49.384075 AND
> tbl_restaurant_location.longitude > -123.03932 AND
> tbl_restaurant_location.longitude < -122.76906 AND distance <= 15.0
> ORDER BY distance;

> ERROR:  Attribute 'distance' not found

It's not related to your function or query, but it's a generic
behaviour:

changemaster=# select id + 1 as next, val from t;next | val
------+------   2 | Test
(1 row)
changemaster=# select id + 1 as next, val from t where next > 1;
ERROR:  Attribute 'next' not found
changemaster=# select id + 1 as next, val from t where id + 1 > 1;next | val
------+------   2 | Test
(1 row)                                                                               
The named expression isn't available in the WHERE clause. You have to
copy the same expression in it.

-- 
Alessio F. Bragadini        alessio@albourne.com
APL Financial Services        http://village.albourne.com
Nicosia, Cyprus             phone: +357-2-755750

"It is more complicated than you think"    -- The Eighth Networking Truth from RFC 1925