MySQL优化之联合索引

wcdz

(root@localhost) [test]> show create table t_demo\G;　　*************************** 1. row ***************************
　　Table: t_demo
　　Create Table: CREATE TABLE `t_demo` (
　　`vin` varchar(17) NOT NULL DEFAULT '' COMMENT '底盘号',
　　`lng` decimal(10,6) DEFAULT NULL COMMENT 'GPS经度',
　　`lat` decimal(10,6) DEFAULT NULL COMMENT 'GPS纬度',
　　`gps_time` datetime DEFAULT NULL,
　　`crmkey` char(36) DEFAULT NULL ,
　　`veh_model_desc` varchar(30) DEFAULT NULL ,
　　`veh_series_desc` varchar(30) DEFAULT NULL ,
　　`update_time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00' ,
　　PRIMARY KEY (`vin`,`update_time`),
　　KEY `idx_crmkey` (`crmkey`)
　　) ENGINE=InnoDB DEFAULT CHARSET=utf8
　　/*!50100 PARTITION BY RANGE (to_days(update_time))
　　(PARTITION p20160724 VALUES LESS THAN (736535) ENGINE = InnoDB,
　　PARTITION p20160725_0731 VALUES LESS THAN (736542) ENGINE = InnoDB,
　　PARTITION p20160801_0807 VALUES LESS THAN (736549) ENGINE = InnoDB,
　　PARTITION p20160808_0814 VALUES LESS THAN (736556) ENGINE = InnoDB,
　　PARTITION p20160815_0821 VALUES LESS THAN (736563) ENGINE = InnoDB,
　　PARTITION p20160822_0828 VALUES LESS THAN (736570) ENGINE = InnoDB,
　　PARTITION p20160829_0904 VALUES LESS THAN (736577) ENGINE = InnoDB,
　　PARTITION p20160905_0911 VALUES LESS THAN (736584) ENGINE = InnoDB,
　　PARTITION p20160912_0918 VALUES LESS THAN (736591) ENGINE = InnoDB,
　　PARTITION p20160919_0925 VALUES LESS THAN (736598) ENGINE = InnoDB,
　　PARTITION p20160926_1002 VALUES LESS THAN (736605) ENGINE = InnoDB,
　　PARTITION p20161003_1009 VALUES LESS THAN (736612) ENGINE = InnoDB,
　　PARTITION p20161010_1016 VALUES LESS THAN (736619) ENGINE = InnoDB,
　　PARTITION p20161017_1023 VALUES LESS THAN (736626) ENGINE = InnoDB,
　　PARTITION p20161024_1030 VALUES LESS THAN (736633) ENGINE = InnoDB,
　　PARTITION p20161031_1106 VALUES LESS THAN (736640) ENGINE = InnoDB,
　　PARTITION p20161107_1113 VALUES LESS THAN (736647) ENGINE = InnoDB,
　　PARTITION p20161114_1120 VALUES LESS THAN (736654) ENGINE = InnoDB,
　　PARTITION p20161121_1127 VALUES LESS THAN (736661) ENGINE = InnoDB,
　　PARTITION p20161128_1204 VALUES LESS THAN (736668) ENGINE = InnoDB,
　　PARTITION p20161205_1211 VALUES LESS THAN (736675) ENGINE = InnoDB,
　　PARTITION p20161212_1218 VALUES LESS THAN (736682) ENGINE = InnoDB,
　　PARTITION p20161219_1225 VALUES LESS THAN (736789) ENGINE = InnoDB,
　　PARTITION p20161226_170101 VALUES LESS THAN (736796) ENGINE = InnoDB) */
　　1 row in set (0.00 sec)