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Re: minus vs. where not exists, vs. where not in

From: Wolfgang Breitling <>
Date: Sun, 21 Sep 2003 11:24:35 -0800
Message-ID: <>

First off, the three are not equivalent, not substitutes for each other. Well not in and minus would be, but they are different from not exists. "not in"/"minus" and "not exists" can return different results. See <>

for examples and explanation.

I have not done any performance comparisons but I personally routinely use minus and I am quite happy with it, especially across a db link.

At 09:59 AM 9/21/2003 -0800, you wrote:
>Do any of you have any cases when minus is superior in performance? Ive
>found 'not in' with a hash_aj to be the best option if the sub-query is
>significantly less 'costly' then the outer query. I dont mean cost in
>terms of the Explain Plan, I mean the work Oracle has to do to find a
>result set. It also depends on a proper hash_area_size
>I find 'where not exists' to be best if the subquery is relatively close
>in cost to the outer query. Yes I know you cant make broad
>generalizations, but there has to be some 'narrow' generalizations you can
>make. Such as certain cases, etc...
>what have you seen? There seems to be very little work in this area in the
>Does 'where not exist' need more or less sort_area_size space than minus?

Wolfgang Breitling
Oracle7, 8, 8i, 9i OCP DBA
Centrex Consulting Corporation

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Author: Wolfgang Breitling

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Received on Sun Sep 21 2003 - 14:24:35 CDT

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