mysql的CREATE TABLE IF NOT EXISTS 方法

DROP TABLE IF EXISTS `ci_sessions`;
CREATE TABLE IF NOT EXISTS `ci_sessions` (
   `session_id` VARCHAR(40) NOT NULL DEFAULT '0',
   `peopleid` INT(11) NOT NULL,
   `ip_address` VARCHAR(16) NOT NULL DEFAULT '0',
   `user_agent` VARCHAR(50) NOT NULL,
   `last_activity` INT(10) UNSIGNED NOT NULL DEFAULT '0',
   `LEFT` INT(11) NOT NULL,
   `name` VARCHAR(25) NOT NULL,
   `status` TINYINT(4) NOT NULL DEFAULT '0'
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

转载于:https://www.cnblogs.com/chenjianhong/archive/2012/08/14/4145008.html