1.查看编码
#显示所有编码和字符校对的参数
SHOW VARIABLES WHERE Variable_name LIKE 'character_set_%' OR Variable_name LIKE 'collation%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8mb4 |
| character_set_connection | utf8mb4 |
| character_set_database | utf8mb4 |
| character_set_filesystem | binary |
| character_set_results | utf8mb4 |
| character_set_server | utf8mb4 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
| collation_connection | utf8mb4_general_ci |
| collation_database | utf8mb4_general_ci |
| collation_server | utf8mb4_general_ci |
+--------------------------+----------------------------+
关注下列变量是否符合我们的要求
character_set_client
character_set_connection
character_set_database
character_set_results
character_set_server
下列三个系统变量我们不需要关心，不会影响乱码等问题
character_set_filesystem
character_set_system
character_sets_dir
2、修改编码为utf8mb4
修改my.cnf文件。加入以下内容，然后重启数据库：systemctl restart mysqld
[mysqld]
character-set-server=utf8mb4
[mysql]
default-character-set=utf8mb4
[client]
default-character-set=utf8mb4
3.已有的库和表更改为utf8mb4
SELECT
CONCAT(
'ALTER TABLE `',
TABLE_NAME,
'` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;'
) AS mySQL
FROM
INFORMATION_SCHEMA. TABLES
WHERE
TABLE_SCHEMA = '你的库名'；
生成可以批量执行的sql语句，导出批量跑一下，ok了