Fw: [PHP-DB] RE: LIMIT and get_num_rows

Apologies to the original post-er, I see that I was getting ahead of myself... http://www.mysql.com/doc/N/u/Nutshell_Other_features.html 1.5.4 Other Features Available From MySQL 4.0.0 ... Functions like SQL_CALC_FOUND_ROWS and FOUND_ROWS() makes it possible to know how many rows a query would have returned without a LIMIT clause. FYI/"Coming soon"/"watch this space"! Regards, =dn ----- Original Message ----- From: "DL Neil" <PHPml@DandE.HomeChoice.co.uk> To: "matt stewart" <matt@netvirtua.com>; <php-db@lists.php.net> Sent: 14 January 2002 14:17 Subject: Re: [PHP-DB] RE: LIMIT and get_num_rows > Have you (original post-er) tested performing a SELECT ... LIMIT 0, 20 and then calling > mysql_num_rows()? > Does it return 20 (the LIMIT) or the number of rows SELECT-ed before/without regard to the > limit? > > =dn > > ----- Original Message ----- > From: "matt stewart" <matt@netvirtua.com> > To: <php-db@lists.php.net> > Sent: 14 January 2002 14:05 > Subject: RE: [PHP-DB] RE: LIMIT and get_num_rows > > > > you've assumed correctly - so it's definitely faster to do the two queries? > > okey dokey, then that's the method i shall use. > > thanks to everyone who's added their thoughts! > > > > -----Original Message----- > > From: Peter Westergaard [mailto:peter@westergaard.ca] > > Sent: 14 January 2002 14:01 > > To: php-db@lists.php.net > > Subject: [PHP-DB] RE: LIMIT and get_num_rows > > > > > > > > >but presumably if i'm doing a SELECT count(*) FROM Designs WHERE Keywords > > >LIKE "%sport%" > > >followed by a SELECT * FROM Designs WHERE Keywords LIKE "%sport%" LIMIT > > 0,20 > > > > > >it's still using nearly as much processing time as just returning all the > > >designs and just using a get_num_rows and then only using the first 20? > > > > I absolutely think it will not. > > > > After all, the table record count should be able to reference the index, > > (you are running this query against an indexed 'Keywords' column yes?), > > while assembling the table of returned data will take quite a bit more > > memory, which is what you're really trying to cut down, I think. > > > > Cheers, > > -Peter > > > > > > -- > > PHP Database Mailing List (http://www.php.net/) > > To unsubscribe, e-mail: php-db-unsubscribe@lists.php.net > > For additional commands, e-mail: php-db-help@lists.php.net > > To contact the list administrators, e-mail: php-list-admin@lists.php.net > > > > --- > > Incoming mail is certified Virus Free. > > Checked by AVG anti-virus system (http://www.grisoft.com). > > Version: 6.0.313 / Virus Database: 174 - Release Date: 02/01/02 > > > > > > --- > > Outgoing mail is certified Virus Free. > > Checked by AVG anti-virus system (http://www.grisoft.com). > > Version: 6.0.313 / Virus Database: 174 - Release Date: 02/01/02 > > > > > > -- > > PHP Database Mailing List (http://www.php.net/) > > To unsubscribe, e-mail: php-db-unsubscribe@lists.php.net > > For additional commands, e-mail: php-db-help@lists.php.net > > To contact the list administrators, e-mail: php-list-admin@lists.php.net > > > > > > > -- > PHP Database Mailing List (http://www.php.net/) > To unsubscribe, e-mail: php-db-unsubscribe@lists.php.net > For additional commands, e-mail: php-db-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net > >