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From: 8q5tmkyqry@sneakemail.com
Date: Mon, 1 Feb 2010 13:31:38 +0000
To: pgsql-sql@postgresql.org
Subject: selecting rows tagged with "a" but not "b"
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Hi,

I have a two tables:

article
articleID, name, content

tags
articleID, tag

I want to find all articles that are tagged with "a" but not "b"

how do I do this?

what I'd like to do is:

<wishful thinking>
select articleID from tags where tag="a"
SUBTRACT
select articleID from tags where tab="b"
</wishful thinking>

how do I do this in real SQL?

thanks

Darrell