From: | Ferindo Middleton Jr <fmiddleton(at)verizon(dot)net> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | showing multiple REFERENCE details of id fields in single query that share the same table |
Date: | 2005-09-15 01:11:37 |
Message-ID: | 4328CA49.7030409@verizon.net |
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Thread: | |
Lists: | pgsql-sql |
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
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