MySQL分区表实现按月份归类

MySQL分区表是一种将大表拆分为多个小表的技术。使用分区表可以明显提高查询效率，减轻数据库服务器的压力。以下是按月份归类数据的完整攻略。

步骤1：创建范围分区表

首先，我们需要在MySQL中创建一个范围分区表，也就是按照时间分区。我们可以通过以下示例代码创建一个按月份归类的范围分区表：

CREATE TABLE user_info (
    uid INT(11) NOT NULL,
    uname VARCHAR(16) NOT NULL,
    register_time DATETIME NOT NULL,
    INDEX idx_register_time (register_time)
)
PARTITION BY RANGE(TO_DAYS(register_time)) (
    PARTITION part_201801 VALUES LESS THAN (TO_DAYS('2018-02-01')),
    PARTITION part_201802 VALUES LESS THAN (TO_DAYS('2018-03-01')),
    PARTITION part_201803 VALUES LESS THAN (TO_DAYS('2018-04-01')),
    PARTITION part_201804 VALUES LESS THAN (TO_DAYS('2018-05-01')),
    PARTITION part_201805 VALUES LESS THAN (TO_DAYS('2018-06-01')),
    PARTITION part_201806 VALUES LESS THAN (TO_DAYS('2018-07-01')),
    PARTITION part_201807 VALUES LESS THAN (TO_DAYS('2018-08-01')),
    PARTITION part_201808 VALUES LESS THAN (TO_DAYS('2018-09-01')),
    PARTITION part_201809 VALUES LESS THAN (TO_DAYS('2018-10-01')),
    PARTITION part_201810 VALUES LESS THAN (TO_DAYS('2018-11-01')),
    PARTITION part_201811 VALUES LESS THAN (TO_DAYS('2018-12-01')),
    PARTITION part_201812 VALUES LESS THAN (TO_DAYS('2019-01-01')),
    PARTITION part_201901 VALUES LESS THAN (TO_DAYS('2019-02-01')),
    PARTITION part_201902 VALUES LESS THAN (TO_DAYS('2019-03-01')),
    PARTITION part_201903 VALUES LESS THAN (TO_DAYS('2019-04-01')),
    PARTITION part_201904 VALUES LESS THAN (TO_DAYS('2019-05-01')),
    PARTITION part_201905 VALUES LESS THAN (TO_DAYS('2019-06-01')),
    PARTITION part_201906 VALUES LESS THAN (TO_DAYS('2019-07-01')),
    PARTITION part_201907 VALUES LESS THAN (TO_DAYS('2019-08-01')),
    PARTITION part_201908 VALUES LESS THAN (TO_DAYS('2019-09-01')),
    PARTITION part_201909 VALUES LESS THAN (TO_DAYS('2019-10-01')),
    PARTITION part_201910 VALUES LESS THAN (TO_DAYS('2019-11-01')),
    PARTITION part_201911 VALUES LESS THAN (TO_DAYS('2019-12-01')),
    PARTITION part_201912 VALUES LESS THAN (TO_DAYS('2020-01-01'))
);

我们可以在数据表中加入一些数据，如下：

INSERT INTO user_info(uid,uname,register_time)
VALUES
(1,'alice','2018-01-01 10:00:00'),
(2,'bob','2018-01-23 11:11:11'),
(3,'carol','2018-01-31 00:59:59'),
(4,'david','2018-02-01 10:00:00'),
(5,'ella','2018-02-14 20:20:20'),
(6,'frank','2018-03-01 00:00:01');

步骤2：查询数据

我们可以使用以下代码对用户信息进行查询，该代码支持按照月份进行查询：

SELECT *
FROM user_info PARTITION (part_201901)
WHERE YEAR(register_time) = '2019' AND MONTH(register_time) = '01';

我们也可以使用以下代码查询所有在2019年1月份之前注册的用户：

SELECT *
FROM user_info
WHERE register_time < '2019-01-01';

以上就是实现按月份归类的完整攻略和两条实例说明。