The commonly used string functions include LENGTH, SUBSTR, CONCAT, UPPER, LOWER, LTRIM, RTRIM, and TRIM.
Note that in a MySQL tenant, the LENGTH function returns string length in bytes while the CHAR_LENGTH function returns string length in characters.
obclient> select length('medium'), char_length('medium');
+---------------+--------------------+
| length('medium') | char_length('medium') |
+---------------+--------------------+
| 3 | 1 |
+---------------+--------------------+
1 row in set (0.00 sec)