Question: If you select and order by an indexed field, so that only the
index file is used, does the server still do a sort, or does the data come
out of the file pre-sorted?
Just wondering
Quentin
-----Original Message-----
From: Cal Evans [mailto:[EMAIL PROTECTED]]
Sent: Friday, 23 February 2001 10:42
To: Adam C Buggia; Jason Landry
Cc: [EMAIL PROTECTED]
Subject: RE: indexing
Nope. ORDER BY determines how the result set is output. It has nothing to
do with how MySQL finds the records.
Cal
http://www.calevans.com
-----Original Message-----
From: Adam C Buggia [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 22, 2001 2:53 PM
To: Jason Landry
Cc: [EMAIL PROTECTED]
Subject: Re: indexing
I do use ORDER BY by meet_hnd DESC.
In trying to optimize queries on this db, can I assume the following:
In searching for a result on meet_hnd (which is indexed) using the ORDER
BY clause not only affects the was the data is returned but also the
method by which the results are searched on:
ORDER BY ... DESC - starts from bottom
ORDER BY ... ASC - starts from top
not specifying order will result in a BDT search.
--------------------
Adam C Buggia
DirectAthletics Inc.
W: 978 927 7188
C: 781 608 5952
On Thu, 22 Feb 2001, Jason Landry wrote:
> > I am the dba for a track and field results web site, when people look
for
> > results they are most likely going to want results from a more recent
meet
> > (rather than older meets).
> >
> > there is a table result and a table meet where a column in result is
> > "meet_hnd." (there maybe hundreds of results per meet) so I have
indexed
> > the result table on meet_hnd. This sped things up dramatically. Now,
the
> > I see it, though we are indexed on meet_hnd, when searching for results
> > mysql is starting at the first meet_hnd though we are most likely
wanting
> > to retrieve the last meet_hnd. If this were indexed in reverse order
than
> > the first meet_hnd would most likely be the one we are looking for.
>
> Have you tried an ORDER BY meet_hnd DESC on your query?
>
>
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