Syntax
------

SET('value1','value2',...) [CHARACTER SET charset_name] [COLLATE
collation_name]

Description
-----------

A set. A string object that can have zero or more values, each of which must
be chosen from the list of values 'value1', 'value2', ... A SET column can
have a maximum of 64 members. SET values are represented internally as
integers.

SET values cannot contain commas.

If a SET contains duplicate values, an error will be returned if strict mode
is enabled, or a warning if strict mode is not enabled.

URL: https://mariadb.com/kb/en/set-data-type/