如果更新失败,MySQL函数插入记录？

DELIMITER //
CREATE FUNCTION insert_user() RETURNS TRIGGER
BEGIN
  INSERT INTO users (name, email, last_updated) VALUES ('John Doe', 'john.doe@example.com', NOW());
  RETURN NEW;
END;
//
DELIMITER ;

DELIMITER //
CREATE TRIGGER insert_user_trigger
AFTER UPDATE ON users
FOR EACH ROW
BEGIN
  IF NEW.last_updated <> OLD.last_updated THEN
    CALL insert_user();
  END IF;
END;
//
DELIMITER ;