MySQL分区表语法解读
作者：Why9310
MySQL分区表主要用于提高查询效率,通过将数据分割成更小的部分进行管理,文章详细介绍了如何创建、查询、修改和存储分区表,包括创建复合主键、按年份和月份分区、删除分区、查询分区数据以及利用存储过程批量转换非分区表为分区表等方法
MySQL分区表语法
1.创建分区表
分区键需要和主键设置为复合主键，分区表不可直接转换成非分区表，需要重新建非分区表并导入数据
- 按年份
CREATE TABLE partitioned_table_year (
id INT,
content VARCHAR(50),
created_time DATETIME,
PRIMARY KEY (id,created_time)
) PARTITION BY RANGE(YEAR(created_time)) (
PARTITION p2024 VALUES LESS THAN (2025),
PARTITION p2025 VALUES LESS THAN (2026),
PARTITION p2026 VALUES LESS THAN (2027)
);- 按月份
CREATE TABLE partitioned_table_month (
id INT,
content VARCHAR(50),
created_time DATETIME,
PRIMARY KEY (id,created_time)
) PARTITION BY RANGE COLUMNS(created_time) (
PARTITION p202410 VALUES LESS THAN ('2024-11-01'),
PARTITION p202411 VALUES LESS THAN ('2024-12-01'),
PARTITION p202412 VALUES LESS THAN ('2025-01-01')
);- 修改表结构，增加分区
ALTER TABLE `partitioned_table_month` MODIFY COLUMN `created_time` datetime(0) NOT NULL ,
DROP PRIMARY KEY,
ADD PRIMARY KEY (`id`, `created_time`) USING BTREE;
ALTER TABLE partitioned_table_month PARTITION BY RANGE COLUMNS(created_time) (
PARTITION p202410 VALUES LESS THAN ('2024-11-01'),
PARTITION p202411 VALUES LESS THAN ('2024-12-01'),
PARTITION p202412 VALUES LESS THAN ('2025-01-01')
);- 删除分区，注意：删除分区的时候会同时删除数据
ALTER TABLE partitioned_table_month DROP PARTITION p202407,p202408;
2.查询
- 查看表分区
SELECT
TABLE_NAME,
PARTITION_NAME,
PARTITION_METHOD,
PARTITION_EXPRESSION,
PARTITION_DESCRIPTION,
TABLE_ROWS,
AVG_ROW_LENGTH,
DATA_LENGTH,
INDEX_LENGTH
FROM
information_schema.PARTITIONS
WHERE
TABLE_SCHEMA = 'xxx' and TABLE_NAME = 'partitioned_table_month'; - 查看分区数据
select * from partitioned_table PARTITION (p2024,p2025)
3.利用存储过程批量修改非分区表为分区表
- 创建联合主键存储过程，先设置联合主键字段非空，再删除原id去掉主键，再设置联合主键
DELIMITER $$
DROP PROCEDURE IF EXISTS auto_create_pk$$
CREATE PROCEDURE `auto_create_pk`(IN `table_name` varchar(64),IN `column_name` varchar(64),IN `column_comment` varchar(64))
BEGIN
SET @sql = CONCAT("ALTER TABLE `",table_name,"` MODIFY COLUMN `",column_name,"` datetime NOT NULL COMMENT '",column_comment,"',
DROP PRIMARY KEY,
ADD PRIMARY KEY ( `id`, `",column_name,"` ) USING BTREE;");
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;- 创建按年自动分区存储过程
DELIMITER $$
DROP PROCEDURE IF EXISTS auto_create_partition_year$$
CREATE PROCEDURE `auto_create_partition_year`(IN `table_name` varchar(64),IN `column_name` varchar(64))
BEGIN
DECLARE partitioned LONGTEXT;
DECLARE n INT;
set n = 2025;
set partitioned = '';
WHILE n <= 2027 DO
SET partitioned = CONCAT(partitioned,",PARTITION p",n," VALUES LESS THAN (",n+1,")");
SET n = n + 1;
END WHILE;
SET @sql = CONCAT ("ALTER TABLE ",table_name," PARTITION BY RANGE(YEAR(",column_name,")) (",SUBSTR(partitioned,2,LENGTH(partitioned)),");") ;
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;- 创建按月自动分区存储过程
DELIMITER $$
DROP PROCEDURE IF EXISTS auto_create_partition_month$$
CREATE PROCEDURE `auto_create_partition_month`(IN `table_name` varchar(64),IN `column_name` varchar(64))
BEGIN
DECLARE partitioned LONGTEXT;
DECLARE n INT;
DECLARE m INT;
set n = 2015;
set partitioned = '';
WHILE n <= 2030 DO
set m = 1;
WHILE m < 12 DO
SET partitioned = CONCAT(partitioned,",PARTITION p",n,LPAD(m,2,0)," VALUES LESS THAN ('",n,"-",LPAD(m+1,2,0),"-01')");
SET m = m + 1;
END WHILE;
IF m = 12 THEN
SET partitioned = CONCAT(partitioned,",PARTITION p",n,"12 VALUES LESS THAN ('",n+1,"-01-01')");
END IF;
SET n = n + 1;
END WHILE;
SET @sql = CONCAT ("ALTER TABLE ",table_name," PARTITION BY RANGE COLUMNS(",column_name,") (",SUBSTR(partitioned,2,LENGTH(partitioned)),");") ;
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;-- 查询存储过程
show procedure status like 'auto_create_partition%';
-- 执行联合主键
CALL auto_create_pk('table_a','a_time','时间');
-- 执行按年自动分区
CALL auto_create_partition_year('table_b','b_time');
-- 执行按月自动分区
CALL auto_create_partition_month('table_c','c_time'); 总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。