help on query

From: "Sziklai Gabor" <gabika(at)interbase(dot)hu>
To: <simeo(at)incofisa(dot)com>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: help on query
Date: 2003-01-18 22:36:23
Message-ID: 001501c2bf42$082b5700$ce6641d9@gabika
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Greetings,

There are several methods:

1/
SELECT idTableB FROM B WHERE idTableA =1
EXCEPT
SELECT idTableB FROM B WHERE idTableA =2

2/
SELECT idTableB, MAX(idTableA)
FROM B
GROUP BY idTableB
HAVING MAX(idTableA) = 1

3/
SELECT idTableB FROM
(SELECT DISTINCT ON (idTableB) idTableB, idTableA
FROM B
ORDER BY idTableB, idTableA DESC) aa
WHERE idTableA = 1

Gabor

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