Re: The most efficient way to put this?

hm, you can try to make a statement with UNION and GROUP by. i dont know
if it is faster...

-----Ursprüngliche Nachricht-----
Von: Arsalan Zaidi [mailto:azaidi(at)directi(dot)com]
Gesendet: Dienstag, 5. März 2002 11:12
An: pgsql-general(at)postgresql(dot)org
Betreff: [GENERAL] The most efficient way to put this?

The query I'd like to run is fairly simple. Unfortunately, PG doesn't
handle
IN's very well.

SELECT DISTINCT ON (aa.a) aa.a, aa.b, aa.c FROM aa WHERE aa.a NOT IN
(select
zz.a from zz);

This is with two very large tables. Both zz and aa have many millions of
rows.

The best I've come up with so far is...

SELECT DISTINCT ON (aa.a) aa.a, aa.b, aa.c FROM aa WHERE NOT EXISTS
(SELECT
zz.a FROM zz WHERE aa.a = zz.a);

Does anyone have anything better?

--Arsalan

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