Re: OR on multiple columns

[David Chamberlin <dwc@nautiboy.com>]

Jason Wong wrote:
> On Thursday 09 January 2003 08:36, David Chamberlin wrote:
>
> > I was reading the mysql docs and noticed a section on searching on
> > multiple keys (stupid question - keys=columns?).  It says doing an OR on
> > multiple keys is inefficient, and you should use a temp table.  Here's
> > their example:
> >
> > CREATE TEMPORARY TABLE tmp
> > SELECT field1_index, field2_index FROM test_table WHERE field1_index = '1';
> > INSERT INTO tmp
> > SELECT field1_index, field2_index FROM test_table WHERE field2_index = '1';
> > SELECT * from tmp;
> > DROP TABLE tmp;
> >
> > My question is, is there a point at which this temp table is less
> > efficient?  
>
> That may depend upon your particular circumstances, and hence running your own 
> tests on both methods would give you the best answer.
OK, so what's the best way to go about profiling this?  Everything runs 
on my ISP's server.

Thanks,
Dave


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