Update Doesn't Update!

[Victor Subervi]

Hi;

mysql> update products set sizes="('Small', 'Large')" where ID=0;
Query OK, 0 rows affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 1

mysql> select sizes, colorsShadesNumbersShort from products where ID=0;
+-------+--------------------------+
| sizes | colorsShadesNumbersShort |
+-------+--------------------------+
|       |                          |
+-------+--------------------------+
1 row in set (0.00 sec)

Huh?
TIA,
Victor