Chris, > SELECT my_id FROM my_table WHERE my_value LIKE '%ABCDEFG%' LIMIT 50; > I know that in a query such as this, mysql does not utilize indexing, so I > was just curious how some others have attempted to speed up this kind of > thing up....
Maybe this answer won't help too much, but I experienced that MySQL _will_ use indexes, even if a LIKE comparison has a match pattern like "%...%" (actually, the discussion is about the leading "%..."). In a 1.2 million records table, I found that a search like that took about 15 seconds without an index, and 2.4 seconds after we created an index on the column in question. I called this effect "pre-sorted comparison", but maybe someone else will have a better explanation. Regards, -- Stefan Hinz <[EMAIL PROTECTED]> CEO / Geschäftsleitung iConnect GmbH <http://iConnect.de> Heesestr. 6, 12169 Berlin (Germany) Telefon: +49 30 7970948-0 Fax: +49 30 7970948-3 ----- Original Message ----- From: "Chris Stark" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, December 16, 2002 10:25 PM Subject: Large Like Queries > Hi, > > I was just wondering if anyone has any tricks for speeding up huge queries > that require a LIKE comparison, and also a wild card at the front and back > of the search term. For example: > > SELECT my_id FROM my_table WHERE my_value LIKE '%ABCDEFG%' LIMIT 50; > > I know that in a query such as this, mysql does not utilize indexing, so I > was just curious how some others have attempted to speed up this kind of > thing up.... > > Thanks, > Chris > > --------------------------------------------------------------------- > 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 > --------------------------------------------------------------------- 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
