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关于mysql的MERGE储存引擎简单例子

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Release: 2016-06-07 16:15:03
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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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