Re: Minus operator

From: Chris Weiss <weisschr_at_pilot.msu.edu>
Date: Wed, 26 May 1999 12:32:45 -0400
Message-ID: <7ih7nn$5gu$1@msunews.cl.msu.edu>

Are you trying to determine the difference between two record sets?? If so, then minus will always be faster provided you have sufficient temp space. Inserting millions of records and then deleting will require many more resources. You could also use an outer join with null link fields, but if your join is too complex or a self-join, this might be too expensive.

You need to size this query carefully before running it. Generate counts first of your record sets before actually performing the query.

I would only run this query in "off-line" time until you know its performance statistics.

Christopher Weiss
Professional Services Division
Compuware Corporation

<dinks01_at_my-dejanews.com> wrote in message news:7igvl9$q3m$1_at_nnrp1.deja.com...
> In a data warehouse operation, where the number
> of rows are in in to region of millions or >,
> what is the most efficient method for determinine
> the differences. Is the Minus op fast conpared to
> someting like doing insert/update ?
>
>
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Received on Wed May 26 1999 - 11:32:45 CDT