MariaDB [test]> select version();

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

| version()       |

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

| 10.3.39-MariaDB |

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

1 row in set (0.000 sec)

MariaDB [test]> create table t ( `fieldname2` int(10) unsigned NOT NULL DEFAULT 0 , `fieldname` int(10) unsigned NOT NULL DEFAULT 0 comment 'lalal' CHECK (`fieldname` <> 0 or `fieldname2` <> 0)  );

Query OK, 0 rows affected (0.002 sec)

MariaDB [test]> show create table t\G

*************************** 1. row ***************************

       Table: t

Create Table: CREATE TABLE `t` (

  `fieldname2` int(10) unsigned NOT NULL DEFAULT 0,

  `fieldname` int(10) unsigned NOT NULL DEFAULT 0 COMMENT 'lalal' CHECK (`fieldname` <> 0 or `fieldname2` <> 0)

) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci

1 row in set (0.000 sec)