That doesn't seem to work (and not with bigger table either): mysql> create temporary table x (y int, z int, index (y), index(z)); insert into x values (1,2), (3,4), (5,6); explain select * from x where y = 1 or z = 1; Query OK, 0 rows affected (0.00 sec)
Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 +-------+------+---------------+------+---------+------+------+-------------+ | table | type | possible_keys | key | key_len | ref | rows | Extra | +-------+------+---------------+------+---------+------+------+-------------+ | x | ALL | y,z | NULL | NULL | NULL | 3 | Using where | +-------+------+---------------+------+---------+------+------+-------------+ 1 row in set (0.00 sec) mysql> quit Bye $ rpm -qa | grep -i mysql perl-DBD-MySQL-1.2216-4 MySQL-devel-4.0.13-0 MySQL-client-4.0.13-0 MySQL-server-4.0.13-0 MySQL-shared-compat-4.0.13-0 (Thanks for your help) On Mon, 4 Aug 2003, Alexander Keremidarski wrote: > Joshua, > > Joshua Spoerri wrote: > > Which version is targetted for optimization of OR searching on two keys, > > that is, "select * from sometable where f1 = 123 or f2 = 123", > > as described in http://www.mysql.com/doc/en/Searching_on_two_keys.html > > ? > > As described there MySQL can use only one index per table. It will work same way > untill next major Optimizer update which is scheduled for 5.1 > > Meanwhile your query can be optimized with using of composite index over both > columns: > > mysql> explain select * from t where f1 = 10 or f2 = 10; > +-------+-------+---------------+------+---------+------+-------+--------------------------+ > | table | type | possible_keys | key | key_len | ref | rows | Extra > | > +-------+-------+---------------+------+---------+------+-------+--------------------------+ > | t | index | f1 | f1 | 10 | NULL | 16384 | Using where; > Using index | > +-------+-------+---------------+------+---------+------+-------+--------------------------+ > > > > > > Thanks > > > > > > -- > Are you MySQL certified? -> http://www.mysql.com/certification > For technical support contracts, visit https://order.mysql.com/?ref=msal > __ ___ ___ ____ __ > / |/ /_ __/ __/ __ \/ / Mr. Alexander Keremidarski <[EMAIL PROTECTED]> > / /|_/ / // /\ \/ /_/ / /__ MySQL AB, Full-Time Developer > /_/ /_/\_, /___/\___\_\___/ Sofia, Bulgaria > <___/ www.mysql.com > > > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
