Can I index just a smaller number of characters from a field even though the field has more? Will this make MySQL to index that field faster?
Teddy, Teddy's Center: http://teddy.fcc.ro/ Email: [EMAIL PROTECTED] ----- Original Message ----- From: "Jeremy Zawodny" <[EMAIL PROTECTED]> To: "David T-G" <[EMAIL PROTECTED]> Cc: "mysql users" <[EMAIL PROTECTED]> Sent: Tuesday, December 31, 2002 1:47 AM Subject: Re: indexing a blob On Mon, Dec 30, 2002 at 04:53:08PM -0500, David T-G wrote: > > Hi, all -- > > Having learned a bit about indexes, I have tried to practice a bit. So > far things work for my char(20) fields, but I have a problem with a > tinyblob. To wit: > > create table ccards > ( > # ID number > id smallint not null default 0 auto_increment primary key , > type smallint not null , # references ccardtypes.id > name char(40) not null , # name as on card > number tinytext not null , # card number > expdate date not null , # expiration date > hashsum tinyblob not null , # hash of the card: have we seen this one? > index (hashsum) # for quick lookups > ) ; > > Whenever I try this with the index, I get > > ERROR 1170 at line 49: BLOB column 'hash' used in key specification > without a key length > > I don't know where the key length needs to be specified; I tried > > hashsum tinyblob(255) not null > > but that puked at the create stage :-) Try this: index (hashsum(123)) # for quick lookups Where 123 is the number of characters/bytes to index. Jeremy -- Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo! <[EMAIL PROTECTED]> | http://jeremy.zawodny.com/ MySQL 3.23.51: up 15 days, processed 557,369,159 queries (408/sec. avg) --------------------------------------------------------------------- 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
