mysql增加创建时间和修改时间记录

DROP TABLE IF EXISTS `mytesttable`;
CREATE TABLE `mytesttable` (
`id` int(11) NOT NULL,
`name` varchar(255) DEFAULT NULL,
`createtime` datetime DEFAULT CURRENT_TIMESTAMP,
`updatetime` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;