我有一个整理问题。它会影响该表的3列，即creation_date，product_id和lastmodified。

我将列更改为utf8mb4，但他们不接受。请看下面。

CREATE TABLE `users` (
  `id` int(32) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `creation_date` datetime DEFAULT NULL,
  `product_id` int(32) DEFAULT NULL,
  `lastmodified` timestamp NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=121 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

查询：

select * from users u where u.name like '%phil臈p%'
No errors, 1 row.

select * from users u where u.creation_date like '%phil臈p%'
Illegal mix of collations for operation 'like'

MySQL系统变量：

show variables like '%character_set%';
character_set_client    utf8
character_set_connection    utf8
character_set_database  utf8
character_set_filesystem    binary
character_set_results   utf8
character_set_server    utf8mb4
character_set_system    utf8

当我手动强制MySQL转换语句中的列时，它确实起作用。

select * from users u where CONVERT(u.creation_date USING utf8mb4) like '%phil臈p%'
No errors; 0 rows;

它不是utf8mb4格式吗？

将不胜感激。