=?iso-8859-1?q?Gary=20Cowell?= <gary_cowell@yahoo.co.uk> writes:
So it seems the idea that oracle is dropping duplicate
rows prior to the sort when using distinct may indeed
be the case.
Okay. We won't have any short-term solution for making DISTINCT do that,
but if you are on PG 7.4 you could get the same effect from using
GROUP BY: instead of
select distinct version from vers where version is not null
try
select version from vers where version is not null group by version
You should get a HashAggregate plan out of that, and I'd think it'd be
pretty quick when there are not many distinct values of version.

regards, tom lane

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postedJun 18, '04 at 11:32a
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