DELIMITER //
CREATE PROCEDURE create_system_user()
BEGIN
IF (SELECT COUNT(*) FROM `user_test` where `user_test`.`username` = 'system') = 0 THEN
INSERT INTO `user_test` (`username`) VALUES ('system');
END IF;
END; //
Results in:
Unknown command: /. Use `/help;` for a list of command.
Repro:
Results in: