Date: Wed, 14 Sep 2005 21:11:37 -0400
From: Ferindo Middleton Jr <fmiddleton@verizon.net>
Subject: showing multiple REFERENCE details of id fields in single query that
	share the same table
To: pgsql-sql@postgresql.org
Reply-To: fmiddleton@verizon.net
Message-id: <4328CA49.7030409@verizon.net>
Organization: Sleek Collar
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I have a table which has two id fields which REFERENCE data back at 
another table. It's setup like this:

class_prerequisite_bindings(id   SERIAL, class_id     INTEGER REFERENCES 
classes(id),   prerequisite    INTEGER REFERENCES classes(id))

The classes table is like this:
classes(id        SERIAL, course_title    TEXT, course_code    TEXT)

I have the following query:
SELECT * FROM class_prerequisite_bindings, classes WHERE 
class_prerequisite_bindings.class_id = 64 AND 
class_prerequisite_bindings.class_id = classes.id;

If I run the query above, the result will only give me info about the 
class_id field matching id 64 back in the classes table. PROBLEM: I want 
this query to also show the info about the prerequisite field which 
would also have info at the classes table. This query will only show the 
course_title and course_code of the class_id but I need this for the 
prerequisite field as well. I think I need to do a JOIN, but I don't 
understand how. How can I do this?

Ferindo