MariaDB [test]> select  version();
+--------------------+
| version()          |
+--------------------+
| 5.5.34-MariaDB-log |
+--------------------+
1 row in set (0.03 sec)

MariaDB [test]> create table `table` (`column` int not null);
Query OK, 0 rows affected (0.22 sec)

MariaDB [test]> ALTER TABLE table MODIFY COLUMN column INT NULL;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that
corresponds to your MariaDB server version for the right syntax to use near 'tab
le MODIFY COLUMN column INT NULL' at line 1

MariaDB [test]> ALTER TABLE `table` MODIFY COLUMN `column` INT NULL;
Query OK, 0 rows affected (0.36 sec)
Records: 0  Duplicates: 0  Warnings: 0