小编die*_*rre的帖子

我有下表：

CREATE TABLE `tokens` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `s_id` int(10) unsigned NOT NULL,
  `a_token` char(40) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
  `a_token_exp` int(10) unsigned NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `u_a_token` (`a_token`) USING HASH,
  KEY `f_seid` (`s_id`),
  CONSTRAINT `f_seid` FOREIGN KEY (`s_id`) REFERENCES `sessions` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=34 DEFAULT CHARSET=latin1

我想更改字符集，a_token因为我们使用以下命令仅使用 ascii 字符：

ALTER TABLE tokens MODIFY a_token CHAR(40) CHARACTER SET ascii COLLATE ascii_general_ci NOT NULL; …