https://stackoverflow.com/questions/53741107/mysql-in-docker-on-ubuntu-warning-world-writable-config-file-is-ignored

修改权限 -> 重启mysql

# 检查字符集配置
SHOW VARIABLES WHERE Variable_name IN (
  'character_set_server', 
  'character_set_database'
);

+------------------------+---------+
| Variable_name          | Value   |
+------------------------+---------+
| character_set_database | utf8mb4 |
| character_set_server   | utf8mb4 |
+------------------------+---------+
2 rows in set (0.00 sec)