Re: Please HELP

From: <prochak_at_my-dejanews.com>
Date: Thu, 17 Dec 1998 20:28:45 GMT
Message-ID: <75bphq$9k0$1@nnrp1.dejanews.com>

In article <3678376B.670_at_cc.utexas.edu>, j.lyons_at_cc.utexas.edu wrote:
> mike_pinker_at_iint.com wrote:
>
> > Yes, the solution would work but using UPPER(THENAME) in the WHERE clause
> > would prohibit the use of any index on the THENAME column ( forcing a full
> > table scan). You could add another column called THENAME_UPPER which is
> > populated with the THENAME in capitals on insert ( e.g. by a trigger ).
Index
> > this column and you could then use the select below:
> >
> > SELECT * FROM MYTABLE WHERE THENAME_UPPER LIKE '%WOOD%';
>
> Would an index be used in a LIKE comparison which is not anchored
> at the start? I believe "... LIKE 'WOOD%'" could use an index
> but not "...LIKE '%WOOD%".
>

Yes, a leading wildcard prevents the index from being used.

--
Ed Prochak
Magic Interface, Ltd.
440-498-3702

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