MySQL DEFAULT vs. MariaDB DEFAULT - mysql

Question

I have table_a with and auto_increment column named id and string column named name.
Running the statement:
INSERT INTO table_a(id, name)VALUES(DEFAULT, 'test');
Results to (MySQL):
+----+------+
| id | name |
+----+------|
| 1 | test |
+----+------+
Running the similar statement in MariaDB results to:
+----+------+
| id | name |
+----+------|
| 0 | test |
+----+------+
Other scenario:
I tried editing the AUTO_INCREMENT value of the table to 30. MySQL inserts 30 while MariaDB inserts 0.
What is the difference of DEFAULT value in INSERT statement of MySQL and MariaDB? Is this a bug in MariaDB or it is working as intended?

Answer 1

This behavior is controlled by SQL_MODE='NO_AUTO_VALUE_ON_ZERO', both in MySQL and MariaDB. If you observe the difference, it's most likely because you have different sql_mode on the instances.
MariaDB [test]> CREATE TABLE t (id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY);
Query OK, 0 rows affected (0.20 sec)
MariaDB [test]> SET SQL_MODE='';
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> INSERT INTO t (id) VALUES (DEFAULT);
Query OK, 1 row affected (0.05 sec)
MariaDB [test]> SELECT * FROM t;
+----+
| id |
+----+
| 1 |
+----+
1 row in set (0.00 sec)
MariaDB [test]> DROP TABLE t;
Query OK, 0 rows affected (0.14 sec)
MariaDB [test]> CREATE TABLE t (id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY);
Query OK, 0 rows affected (0.30 sec)
MariaDB [test]> SET SQL_MODE='NO_AUTO_VALUE_ON_ZERO';
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> INSERT INTO t (id) VALUES (DEFAULT);
Query OK, 1 row affected (0.03 sec)
MariaDB [test]> SELECT * FROM t;
+----+
| id |
+----+
| 0 |
+----+
1 row in set (0.00 sec)