CREATE TABLE `stats` (
  `day` date NOT NULL DEFAULT '2010-06-01',
  `file` char(255) NOT NULL DEFAULT '',
  `size` bigint(20) unsigned NOT NULL,
  `count` int(32) unsigned NOT NULL DEFAULT '0',
  `server` char(32) NOT NULL DEFAULT '',
  `domain` char(32) NOT NULL DEFAULT '',
  `filesize` int(32) NOT NULL DEFAULT '0',
  `month` int(32) unsigned NOT NULL DEFAULT '1',
  `unixday` bigint(20) unsigned NOT NULL,
  `daystamp` int(16) NOT NULL DEFAULT '0',
  PRIMARY KEY (`server`,`domain`,`file`,`day`),
  KEY `file_idx` (`file`),
  KEY `server_idx` (`server`),
  KEY `domain_idx` (`domain`),
  KEY `day_idx` (`day`),
  KEY `daystamp_idx` (`daystamp`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
/*!50100 PARTITION BY LIST (MONTH(day))
(PARTITION p1 VALUES IN (1) ENGINE = MyISAM,
 PARTITION p2 VALUES IN (2) ENGINE = MyISAM,
 PARTITION p3 VALUES IN (3) ENGINE = MyISAM,
 PARTITION p4 VALUES IN (4) ENGINE = MyISAM,
 PARTITION p5 VALUES IN (5) ENGINE = MyISAM,
 PARTITION p6 VALUES IN (6) ENGINE = MyISAM,
 PARTITION p7 VALUES IN (7) ENGINE = MyISAM,
 PARTITION p8 VALUES IN (8) ENGINE = MyISAM,
 PARTITION p9 VALUES IN (9) ENGINE = MyISAM,
 PARTITION p10 VALUES IN (10) ENGINE = MyISAM,
 PARTITION p11 VALUES IN (11) ENGINE = MyISAM,
 PARTITION p12 VALUES IN (12) ENGINE = MyISAM) */ |


mysql> explain partitions select * from stats where MONTH(day)=10;
+----+-------------+-------+----------------------------------------+------+---------------+------+---------+------+---------+-------------+
| id | select_type | table | partitions                             | type | possible_keys | key  | key_len | ref  | rows    | Extra       |
+----+-------------+-------+----------------------------------------+------+---------------+------+---------+------+---------+-------------+
|  1 | SIMPLE      | stats | p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12 | ALL  | NULL          | NULL | NULL    | NULL | 9530547 | Using where |
+----+-------------+-------+----------------------------------------+------+---------------+------+---------+------+---------+-------------+
1 row in set (0.00 sec)