I am trying to insert one record into dim\_channel table with zero for the primary key (unsigned int). 

Mysql command:

```
INSERT INTO dim_channel 
set channel_id=0,name='Other',parent_channel_id=0,parent_channel_name='Other';

```

Results:

```
select * from dim_channel;
+------------+-------+-------------------+---------------------+
| channel_id | name  | parent_channel_id | parent_channel_name |
+------------+-------+-------------------+---------------------+
|          1 | Other |                 0 | Other               |
+------------+-------+-------------------+---------------------+

```

Please note that channel\_id got value 1, not 0 as I expected.

Any one knows why this happens. 

By the way, I can update the record as:
update dim\_channel set channel\_id=0 where channel\_id=1;

Just want to know why I can't insert the record with channel\_id=0 at the first place.

Thanks a lot.

====== MySQL command for you to test ====

-- Create table

```
CREATE TABLE `dim_channel` (
  `channel_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` char(80) DEFAULT NULL,
  `parent_channel_id` int(10) unsigned NOT NULL DEFAULT '0',
  `parent_channel_name` varchar(80) DEFAULT NULL,
  PRIMARY KEY (`channel_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1

```

-- insert record

```
INSERT INTO dim_channel set channel_id=0,name='Other',parent_channel_id=0,parent_channel_name='Other';

```

-- see result

```
select * from dim_channel;

```