Тут. Читать полностью, с комментариями. Должно получиться вот что в итоге:
MariaDB [(none)]> 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 |
| collation_connection | utf8mb4_unicode_520_ci |
| collation_database | utf8mb4_unicode_520_ci |
| collation_server | utf8mb4_unicode_520_ci |
+--------------------------+------------------------+
10 rows in set (0.021 sec)