열의 칼럼의 값을 수정하려하는데 잘 안되네요

desc bbs;
+--------------+---------------+------+-----+---------+-------+
| Field        | Type          | Null | Key | Default | Extra |
+--------------+---------------+------+-----+---------+-------+
| bbsID        | int           | NO   | PRI | NULL    |       |
| bbsTitle     | varchar(20)   | YES  |     | NULL    |       |
| userID       | varchar(20)   | YES  |     | NULL    |       |
| bbsDate      | datetime      | YES  |     | NULL    |       |
| bbsContent   | varchar(2048) | YES  |     | NULL    |       |
| bbsAvailable | int           | YES  |     | NULL    |       |
| count        | int           | YES  |     | NULL    |       |
+--------------+---------------+------+-----+---------+-------+

여기서 count 칼럼의값을

mysql> update bbs set count = count+10 where bbsID=1;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0 

로 수정했는데 (성공됬다고 하는데)
막상 셀렉트해서보면 null로 나와있네요

mysql> select userID, count from bbs where bbsID = 1;
+---------+-------+
| userID  | count |
+---------+-------+
| gildong |  NULL |
+---------+-------+
1 row in set (0.00 sec)

왜이런거죠.