"Mojtaba Faridzad" <[EMAIL PROTECTED]> wrote: > I'm learning MySQL and I got two question: > > 1) As I know, MySQL has a buffer to keep the last records which have been retreived. > So if I run a query two times, the second time will be faster. How can I temporarly > stop this service? because I want to run different queries and compare their speed > and find the best solution for a problem. > > 2) A table has 2 fields, Active CHAR(1), and Company CHAR(40). Sometimes I want to > search a company name and sometimes I want to search an active company. For faster > searching, do I need to create two index like these: > CREATE INDEX active ON customer (CONCAT(active, company)); > CREATE INDEX company ON customer (company); > > If I create just the first index, do I still have a fast searching on company name ( > without mentioning Active )? like this: > SELECT * FROM customer WHERE company = 'my test company';
Nope. If you have index only on (active, company), it will not be used in the above query. -- For technical support contracts, goto https://order.mysql.com/?ref=ensita This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Victoria Reznichenko / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net <___/ www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
