A SET is a string object that can have zero or more values, each of which must be chosen from a list of permitted values specified when the table is created. SET column values that consist of multiple set members are specified with members separated by commas (“,”). A consequence of this is that SET member values should not themselves contain commas.
Example
mysql> CREATE TABLE myset (col SET(‘a’, ‘b’, ‘c’, ‘d’));
Query OK, 0 rows affected (0.43 sec)
mysql> select * from myset;
Empty set (0.20 sec)
mysql> insert into myset value(‘p’);
Query OK, 1 row affected, 1 warning (0.23 sec)
mysql> select * from myset;
+——+
| col |
+——+
| |
+——+
1 row in set (0.10 sec)
mysql> insert into myset value(‘a’);
Query OK, 1 row affected (0.18 sec)
mysql> select * from myset;
+——+
| col |
+——+
| |
| a |
+——+
2 rows in set (0.00 sec)
mysql> insert into myset value(‘p,a’);
Query OK, 1 row affected, 1 warning (0.07 sec)
mysql> select * from myset;
+——+
| col |
+——+
| |
| a |
| a |
+——+
3 rows in set (0.00 sec)