I have a question about determining which case
occurred when there are no matches - using two tables.
Scenario:
- two tables, one for photos, and one for collections
- zero or more photos can belong to a collection
- the database may not know the collection_id requested
(i.e. the user on the browser side did something to request
a non-existent collection)
We can hit:
a) no collection
b) a collection that hasn't had any photos moved/uploaded to it yet, or..
c) a collection with one or more photos (the "normal, everything's fine" case)
Here's the php setting up the query...
// shortened version for posting question...
// there are many more fields...
$sql_str =<<<EOD
select
photo.photo_id AS photo_id,
collection.collection_dir AS collection_dir
from photo, collection
where photo.collection_id = $collection
and collection.collection_id = $collection
EOD;
$sql_result = $db->query($sql_str);
When I check the number of rows returned, and get
0, I have no way (yet) of knowing why (no collection,
or just no photos in a collection).
Should I be using COUNT/GROUP BY?
thanks for any ideas!
--
Daniel L. Smith - [EMAIL PROTECTED] - Sonoma County, CA
AIM: JavaE36M3 ICQ: 12834734
http://resume.daniel.org
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