mysql AUTO_INCREMENT

mysql> CREATE TABLE test
-> (
-> id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT,
-> username VARCHAR(15) NOT NULL
-> )AUTO_INCREMENT = 100;
Query OK, 0 rows affected (0.07 sec)

mysql> show create table test\G;
*************************** 1. row ***************************
Table: test
Create Table: CREATE TABLE `test` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(15) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=100 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

ERROR:
No query specified

mysql> insert into test(username) values('aaa');
Query OK, 1 row affected (0.01 sec)

mysql> select * from test;
+-----+----------+
| id  | username |
+-----+----------+
| 100 | aaa      |
+-----+----------+
1 row in set (0.00 sec)

mysql>  insert into test(username) values('bbb');
Query OK, 1 row affected (0.01 sec)

mysql> select * from test;
+-----+----------+
| id  | username |
+-----+----------+
| 100 | aaa      |
| 101 | bbb      |
+-----+----------+
2 rows in set (0.00 sec)