JWColby
jwcolby at colbyconsulting.com
Sun Jan 21 17:36:40 CST 2007
Thanks Stuart. John W. Colby Colby Consulting www.ColbyConsulting.com -----Original Message----- From: dba-sqlserver-bounces at databaseadvisors.com [mailto:dba-sqlserver-bounces at databaseadvisors.com] On Behalf Of Stuart McLachlan Sent: Sunday, January 21, 2007 5:11 PM To: dba-sqlserver at databaseadvisors.com Subject: Re: [dba-SQLServer] SQL Server indexes Yep, as we discussed just on a month ago. If in general a query returns more than about 10 percent of the records, a table scan is more efficient than an index. On 21 Jan 2007 at 15:43, JWColby wrote: > Am I correct that in a given column, 'Y' and NULL is the "same as" 'Y' > and 'N' or 'Y' and '' (empty string) as far as usefulness of an index > goes? IOW all three of these examples are "two choices" and thus > would likely not benefit from an Index for selection speed? > > John W. Colby > Colby Consulting > www.ColbyConsulting.com > > _______________________________________________ > dba-SQLServer mailing list > dba-SQLServer at databaseadvisors.com > http://databaseadvisors.com/mailman/listinfo/dba-sqlserver > http://www.databaseadvisors.com > -- Stuart _______________________________________________ dba-SQLServer mailing list dba-SQLServer at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/dba-sqlserver http://www.databaseadvisors.com