MariaDB [test]> CREATE TABLE `table` (`id` serial, PRIMARY KEY (id));

Query OK, 0 rows affected (0.052 sec)

MariaDB [test]> show create table `table`;

+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| Table | Create Table                                                                                                                                                     |

+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| table | CREATE TABLE `table` (

  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,

  PRIMARY KEY (`id`),

  UNIQUE KEY `id` (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.004 sec)