如何消除 MySQL表中的字段特别设置的字符集和排序规则?

重新指定字段字符集即可(排序规则默认)

CREATE TABLE `t1` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `serial_no` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;alter table t1 modify `serial_no` varchar(50) CHARACTER SET utf8mb4 NOT NULL;show create table t1;/*CREATE TABLE `t1` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `serial_no` varchar(50) NOT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4*/

mysql 有语句可以重新指定全表字符集。

  

   CREATE TABLE `t1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `serial_no` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
  

执行语句：

  

   ALTER TABLE t1 CONVERT TO CHARACTER SET utf8mb4;
  

CREATE TABLE t1 (
id int NOT NULL AUTO_INCREMENT,
serial_no varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

官方文档介绍
To change the table default character set and all character columns (CHAR, VARCHAR, TEXT) to a new character set, use a statement like this:

ALTER TABLE tbl_name CONVERT TO CHARACTER SET charset_name;