mysql8.0.17+heidisql触发器问题

Question

代码如下：
CREATE TRIGGER depart_update AFTER UPDATE
ON department FOR EACH ROW
BEGIN
UPDATE employee SET employee.dno = new.dnumber
WHERE employee.dno = old.dnumber;
END;
错误：
SQL错误（1064）：You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 5
不知道错在了哪里，也找不到''在哪里，求解答，感谢！

Answer 1

WHERE employee.dno = old.dnumber这里的old.dnumber不能这么写吧，old.dnumber应该是一个值才对