In the last episode (Jul 24), Dave Dutcher said:
> I was wondering if somebody could give me any suggestions on how to optimize
> a query I am working on.
>
> This is my table:
>
> CREATE TABLE testdata (
> Begin char(9) NOT NULL default '',
> End char(9) NOT NULL default '',
> UNIQUE KEY BeginEndIndex (Begin,End)
> ) TYPE=MyISAM;
>
> It is a table of ranges. i.e. 1-5, 7-11, 20000-24000. None of the ranges
> overlap, and I'm trying to write a query to find a range that contains a
> specific number such as 500,000. So this is what I've written for a query:
>
> select Begin, End
> from testdata
> where begin <= '005000000' and end >= '005000000'
Put an index on (begin,end). It will only have to do a range scan on
that index to find the matching records. You might also want to make
those columns integers instead of chars; they'll take up a bit less
space that way.
--
Dan Nelson
[EMAIL PROTECTED]
---------------------------------------------------------------------
Before posting, please check:
http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
To request this thread, e-mail <[EMAIL PROTECTED]>
To unsubscribe, e-mail <[EMAIL PROTECTED]>
Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
