INSERT INTO A (`id`) VALUES (NULL)

Column 'id' cannot be null

INSERT INTO A (`id`) values (0)

drop table if exists A;
create table A
(
id int unsigned not null auto_increment primary key
)
engine=innodb;

insert into A (id) values (null),(null);

mysql> select * from A order by id;
+----+
| id |
+----+
|  1 |
|  2 |
+----+
2 rows in set (0.00 sec)

INSERT INTO `A` VALUES ()