关于mysql的MERGE储存引擎简单例子
关于mysql的MERGE存储引擎简单例子 关于mysql的MERGE存储引擎简单例子 作用:可以将多个表结构相同的表 和合并到一个表中 版本支持:mysql5.1 如下例子: 假设有如下几个表:结构完全相同 article_0,article_1,article_2,article_3, -- Table article_0 D
关于mysql的MERGE存储引擎简单例子关于mysql的MERGE存储引擎简单例子
作用:可以将多个表结构相同的表 和合并到一个表中
版本支持:mysql5.1
如下例子:
假设有如下几个表:结构完全相同 article_0,article_1,article_2,article_3,
-- Table "article_0" DDL
CREATE TABLE `article_0` (
`id` bigint(20) NOT NULL,
`subject` varchar(200) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
-- Table "article_1" DDL
CREATE TABLE `article_1` (
`id` bigint(20) NOT NULL,
`subject` varchar(200) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
-- Table "article_2" DDL
CREATE TABLE `article_2` (
`id` bigint(20) NOT NULL,
`subject` varchar(200) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
-- Table "article_3" DDL
CREATE TABLE `article_3` (
`id` bigint(20) NOT NULL,
`subject` varchar(200) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
建立总表:article_total 结构如下:
-- Table "article_total" DDL
CREATE TABLE `article_total` (
`id` bigint(20) NOT NULL,
`subject` varchar(200) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MRG_MyISAM DEFAULT CHARSET=utf8 UNION=(`article_0`,`article_1`,`article_2`,`article_3`);
那么 article_total 表的内容就包含了article_0`,`article_1`,`article_2`,`article_3`的内容
select * from article_total 表的结果就是各个表述数据合并的内容
修改合并哪些子表的命令:
ALTER TABLE article_total union =(article_0,article_1,article_2,article_3)

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