SET
SET('value', ...) [CHARACTER SET character_set] [COLLATE collation]The SET data type is similar to ENUM, except that
a SET column can hold multiple values (e.g.,
UPDATE table1 SET col1 = 'a, b';). For this data
type, values may be filtered with the
FIND_IN_SET() function. If you want to use a
character set for the column other than the default for the table, you
can give one for the column. Values are sorted based on the collation
of the character set for the column.