Re: Indices

From: Peter Connolly <peter_at_wpi.edu>
Date: 2000/05/03
Message-ID: <Pine.OSF.4.21.0005031230520.28854-100000@wpi.WPI.EDU>#1/1

You can use a multi-column index only if you access the leftmost columns of the index. For example, if you declare an index on columns (A,B,C) in that order then you can use the index if you refer to column A,A and B or A and B and C. You could not use this index on B, C, or B and C, because you do not access all columns to the left.

-Peter

> "craibuc" <craibucNOcrSPAM_at_hotmail.com.invalid> wrote in message
> news:055c9c20.bcb6cb5e_at_usw-ex0105-035.remarq.com...
> > If I have a multi-column index on a table, and I only use a
> > subset of the index's columns in a query, will the index be
> > used? What are the rules?
> >
> > * Sent from RemarQ http://www.remarq.com The Internet's Discussion Network
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Received on Wed May 03 2000 - 00:00:00 CDT