mysql建立表 |
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mysql快速建表的语句写法并不复杂,下面就为您详细介绍两种最常用的mysql快速建表的语句: 1:create table t_select select * from t_old where1=0; 2:create table t_select1 like t_old; 但是***种mysql快速建表的语句有缺陷,他能取消原来表的有些定义。(手册上说Some conversion of data types might occur. For example, the AUTO_INCREMENT attribute is not preserved, and VARCHAR columns can become CHAR columns. ) 可以看看下面的例子 create table t_old (id serial, content varchar(8000) not null,`desc` varchar(100) not null) engine innodb; show CREATE table t_old; | Table | Create Table | t_old | CREATE TABLE `t_old` ( `id` bigint(20) unsigned NOT NULL auto_increment, `content` varchar(8000) NOT NULL, `desc` varchar(100) NOT NULL, UNIQUE KEY `id` (`id`) )ENGINE=InnoDBDEFAULTCHARSET=utf8 create table t_select select * from t_old where1=0; CREATE TABLE `t_select` ( `id` bigint(20) unsigned NOT NULL default '0', `content` varchar(8000) NOT NULL, `desc` varchar(100) NOT NULL )ENGINE=MyISAMDEFAULTCHARSET=utf8 这样 自增字段跟表引擎都变了 如果想要保持一样的引擎,就加上:engine innodb 如: create table t_select engine innodb select * from t_old where1=0; create table t_like like t_old; show CREATE table t_like; Table | t_like | CREATE TABLE `t_like` ( `id` bigint(20) unsigned NOT NULL auto_increment, `content` varchar(8000) NOT NULL, `desc` varchar(100) NOT NULL, UNIQUE KEY `id` (`id`) )ENGINE=InnoDBDEFAULTCHARSET=utf8 这样引擎跟自增字段都没有变 看下面一个一个例子,就知道有什么变化了 CREATE TABLE `t4_innodb` ( `id` int(11) NOT NULL AUTO_INCREMENT, `a1` int(11) NOT NULL, `a2` int(11) DEFAULT NULL, `remark` varchar(200) NOT NULL, PRIMARY KEY (`id`), KEY `a1_2_idx` (`a1`) )ENGINE=InnoDBDEFAULTCHARSET=utf8 create table t6_innodb select * from t4_innodb where1=2; CREATE TABLE `t6_innodb` ( `id` int(11) NOT NULL DEFAULT '0', `a1` int(11) NOT NULL, `a2` int(11) DEFAULT NULL, `remark` varchar(200) NOT NULL )ENGINE=InnoDBDEFAULTCHARSET=utf8 create table t8_innodb like t4_innodb; CREATE TABLE `t8_innodb` ( `id` int(11) NOT NULL AUTO_INCREMENT, `a1` int(11) NOT NULL, `a2` int(11) DEFAULT NULL, `remark` varchar(200) NOT NULL, PRIMARY KEY (`id`), KEY `a1_2_idx` (`a1`) )ENGINE=InnoDBDEFAULTCHARSET=utf8 【编辑推荐】 【责任编辑:段燃 TEL:(010)68476606】 点赞 0 |
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