MariaDB [test2]> CREATE TABLE `testtable` (
    ->   `id` int(11) NOT NULL AUTO_INCREMENT,
    ->   PRIMARY KEY (`id`)
    -> );
Query OK, 0 rows affected (0.01 sec)

MariaDB [test2]> SHOW TABLE STATUS;
+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-------------------+----------+----------------+---------+
| Name      | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time         | Update_time | Check_time | Collation         | Checksum | Create_options | Comment |
+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-------------------+----------+----------------+---------+
| testtable | InnoDB |      10 | Compact    |    0 |              0 |       16384 |               0 |            0 |         0 |              1 | 2014-01-22 19:29:18 | NULL        | NULL       | latin1_swedish_ci |     NULL |                |         |
+-----------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-------------------+----------+----------------+---------+
1 row in set (0.00 sec)

MariaDB [test2]> CREATE DEFINER=`unknownuser`@`%` SQL SECURITY DEFINER VIEW `testview` AS SELECT testtable.id FROM testtable GROUP BY testtable.id;
Query OK, 0 rows affected, 1 warning (0.00 sec)

MariaDB [test2]> SHOW WARNINGS;
+-------+------+--------------------------------------------------------------------+
| Level | Code | Message                                                            |
+-------+------+--------------------------------------------------------------------+
| Note  | 1449 | The user specified as a definer ('unknownuser'@'%') does not exist |
+-------+------+--------------------------------------------------------------------+
1 row in set (0.00 sec)

MariaDB [test2]> SHOW TABLE STATUS;
ERROR 1143 (42000): SELECT command denied to user ''@'%' for column 'id' in table 'testtable'
MariaDB [test2]> SHOW WARNINGS;
+-------+------+---------------------------------------------------------------------------+
| Level | Code | Message                                                                   |
+-------+------+---------------------------------------------------------------------------+
| Error | 1143 | SELECT command denied to user ''@'%' for column 'id' in table 'testtable' |
| Note  | 1449 | The user specified as a definer ('unknownuser'@'%') does not exist        |
+-------+------+---------------------------------------------------------------------------+
2 rows in set (0.00 sec)

MariaDB [test2]> SELECT USER();
+----------------+
| USER()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)