分类: Mysql/postgreSQL
2010-10-12 14:09:28
1、create table t_name select ...
2、create table t_name like ...
第一种会取消掉原来表的有些定义,且引擎是系统默认引擎。
手册上是这么讲的:Some conversion of data types might occur. For example, the AUTO_INCREMENT attribute is not preserved, and VARchar columns can become char columns.
第二种就完全复制原表。
先建立测试表:
以下是代码片段: mysql> create database dbtest; Query OK, 1 row affected (0.03 sec) mysql> use dbtest; Database changed mysql> create table t_old -> ( -> id serial, -> content varchar(8000) not null, -> `desc` varchar(100) not null) -> engine innodb; Query OK, 0 rows affected (0.04 sec) mysql> 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=InnoDB DEFAULT charSET=latin1 | +-------+----------------------------------------------------+ 1 row in set (0.00 sec) |
第一种方式:
以下是代码片段: mysql> create table t_select select * from t_old where 1 = 0; Query OK, 0 rows affected (0.04 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> show create table t_select; +----------+--------------------------------------------+ | Table | create Table +----------+---------------------------------------------+ | t_select | create TABLE `t_select` ( `id` bigint(20) unsigned NOT NULL default ’0’, `content` varchar(8000) NOT NULL, `desc` varchar(100) NOT NULL ) ENGINE=MyISAM DEFAULT charSET=latin1 | +----------+-------------------------------------------+ 1 row in set (0.00 sec) |
第二种方式:
以下是代码片段: mysql> create table t_like like t_old; Query OK, 0 rows affected (0.02 sec) mysql> show create table t_like; +--------+-------------------------------------------------+ | Table | create 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=InnoDB DEFAULT charSET=latin1 | +--------+-------------------------------------------------+ 1 row in set (0.00 sec) mysql> |