我最近接手了一个10年前创建的老项目。它使用MySQL 5.1。

除此之外，我需要将默认字符集从latin1更改为utf8。

举个例子，我有这样的表格:

  CREATE TABLE `users` (
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `first_name` varchar(45) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL,
    `last_name` varchar(45) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL,
    `username` varchar(127) CHARACTER SET latin1 COLLATE latin1_general_ci NOT NULL,
    `email` varchar(127) CHARACTER SET latin1 COLLATE latin1_general_ci NOT NULL,
    `pass` varchar(20) CHARACTER SET latin1 COLLATE latin1_general_ci NOT NULL,
    `active` char(1) CHARACTER SET latin1 COLLATE latin1_general_ci NOT NULL DEFAULT 'Y',
    `created` datetime NOT NULL,
    `last_login` datetime DEFAULT NULL,
    `author` varchar(1) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT 'N',
    `locked_at` datetime DEFAULT NULL,
    `created_at` datetime DEFAULT NULL,
    `updated_at` datetime DEFAULT NULL,
    `ripple_token` varchar(36) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL,
    `ripple_token_expires` datetime DEFAULT '2014-10-31 08:03:55',
    `authentication_token` varchar(255) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL,
    PRIMARY KEY (`id`),
    UNIQUE KEY `index_users_on_reset_password_token` (`reset_password_token`),
    UNIQUE KEY `index_users_on_confirmation_token` (`confirmation_token`),
    UNIQUE KEY `index_users_on_unlock_token` (`unlock_token`),
    KEY `users_active` (`active`),
    KEY `users_username` (`username`),
    KEY `index_users_on_email` (`email`)
  ) ENGINE=InnoDB AUTO_INCREMENT=1677 DEFAULT CHARSET=utf8 CHECKSUM=1 DELAY_KEY_WRITE=1 ROW_FORMAT=DYNAMIC

我设置了自己的Mac来处理这个。没有考虑太多，我运行“brew install mysql”安装mysql 5.7。所以我有一些版本冲突。

我下载了这个数据库的副本并导入了它。

如果我试着像这样运行查询:

  ALTER TABLE users MODIFY first_name varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci    NOT NULL  

我得到这个错误:

  ERROR 1292 (22007): Incorrect datetime value: '0000-00-00 00:00:00' for column 'created' at row 1

我想我可以用:

  ALTER TABLE users MODIFY created datetime  NULL DEFAULT '1970-01-01 00:00:00';
  Query OK, 0 rows affected (0.06 sec)
  Records: 0  Duplicates: 0  Warnings: 0

但我明白:

  ALTER TABLE users MODIFY first_name varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci    NOT NULL ;
  ERROR 1292 (22007): Incorrect datetime value: '0000-00-00 00:00:00' for column 'created' at row 1

我必须更新每个值吗?