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关于分区表函数YEARWEEK无效的疑问。

发布时间: 2012-04-25 19:32:32 作者: rapoo

关于分区表,函数YEARWEEK无效的疑问。

SQL code
DROP TABLE IF EXISTS `part_test`;CREATE TABLE `part_test` (  `id` mediumint(9) NOT NULL AUTO_INCREMENT,  `date` date NOT NULL,  PRIMARY KEY (`id`,`date`)) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_bin  AUTO_INCREMENT=5 ;-- -- 导出表中的数据 `part_test`-- INSERT INTO `part_test` (`id`, `date`) VALUES (3, '2012-01-03'),(4, '2012-01-22');--分区ALTER TABLE `part_test` PARTITION BY RANGE(yearweek(date)) (       PARTITION p201201 VALUES LESS THAN (201202),    PARTITION p201202 VALUES LESS THAN (201203),    PARTITION p201203 VALUES LESS THAN (201204),    PARTITION p201204 VALUES LESS THAN (201205));//下边应该是属于今年的第三个星期的也就是等于201203 ,预计查询不会访问第一分区(p201201)才对,但是执行结果是扫描了不该扫描的第一个分区mysql> explain partitions SELECT count(*) FROM `part_test` WHERE `date` > '2012-01-08';+----+-------------+-----------+---------------------------------+-------+---------------+---------+---------+------+------+--------------------------+| id | select_type | table     | partitions                      | type  | possible_keys | key     | key_len | ref  | rows | Extra                    |+----+-------------+-----------+---------------------------------+-------+---------------+---------+---------+------+------+--------------------------+|  1 | SIMPLE      | part_test | p201201,p201202,p201203,p201204 | index | NULL         | PRIMARY | 6       | NULL |    2 | Using where; Using index |+----+-------------+-----------+---------------------------------+-------+---------------+---------+---------+------+------+--------------------------+1 row in set (0.00 sec)



但是用TO_DAYS函数就符合我的扫描预期。
SQL code
DROP TABLE IF EXISTS `part_test`;CREATE TABLE `part_test` (  `id` mediumint(9) NOT NULL AUTO_INCREMENT,  `date` date NOT NULL,  PRIMARY KEY (`id`,`date`)) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_bin  AUTO_INCREMENT=5 ;-- -- 导出表中的数据 `part_test`-- INSERT INTO `part_test` (`id`, `date`) VALUES (3, '2012-01-03'),(4, '2012-01-22');ALTER TABLE `part_test` PARTITION BY RANGE(to_days(date)) (       PARTITION p201201 VALUES LESS THAN (to_days('2012-01-08')),    PARTITION p201202 VALUES LESS THAN (to_days('2012-01-15')),    PARTITION p201203 VALUES LESS THAN (to_days('2012-01-23')),    PARTITION p201204 VALUES LESS THAN (to_days('2012-01-30')));//下边应该是属于今年的第三个星期的也就是等于201203 ,符合预期mysql> explain partitions SELECT count(*) FROM `part_test` WHERE `date` > '2012-01-16';+----+-------------+-----------+-----------------+--------+---------------+------+---------+------+------+-------+| id | select_type | table     | partitions      | type   | possible_keys | key | key_len | ref  | rows | Extra |+----+-------------+-----------+-----------------+--------+---------------+------+---------+------+------+-------+|  1 | SIMPLE      | part_test | p201203,p201204 | system | NULL          | NULL | NULL    | NULL |    1 |       |+----+-------------+-----------+-----------------+--------+---------------+------+---------+------+------+-------+1 row in set (0.00 sec)


另外付服务器版本信息
SQL code
mysql> \s--------------mysql  Ver 14.14 Distrib 5.1.28-rc, for Win32 (ia32)


谢谢了。

[解决办法]
目前对时间分区 只支持两个函数 year() date()

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