|                 1 |            2 |             2 |                  2 |
+-------------------+--------------+---------------+--------------------+

In Oracle mode from MariaDB 10.3:

SELECT CHAR_LENGTH('π'), LENGTH('π'), LENGTHB('π'), OCTET_LENGTH('π');
+-------------------+--------------+---------------+--------------------+
| CHAR_LENGTH('π')  | LENGTH('π')  | LENGTHB('π')  | OCTET_LENGTH('π')  |
+-------------------+--------------+---------------+--------------------+
|                 1 |            1 |             2 |                  2 |
+-------------------+--------------+---------------+--------------------+

URL: https://mariadb.com/kb/en/lengthb/https://mariadb.com/kb/en/lengthb/