8q5tmky...@sneakemail.com написа:
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?
Replace "SUBSTRACT" with "EXCEPT"
(http://www.postgresql.org/docs/current/static/sql-select.html#SQL-EXCEPT).
--
Milen A. Radev
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