From: Hank
Date: April 19 2005 6:55pm
Subject: Re: zip code search within x miles
List-Archive: http://lists.mysql.com/mysql/182862
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> No, those indexes were intentional.  If you read the section of the manua=
l
> on optimizing queries, you will encounter a page that mentions what are
> known as "covering indexes".  The advantage to a covering index is that i=
f
> your data is numeric and in the index,=20

Except that the zip code field is not (and should not be) numeric, so
the qualification test fails.