使MySQL触发器正常工作时遇到问题（世界数据库）

Question

问题： 创建一个仅在官方语言大于75％且非英语的情况下才删除城市的触发器。

数据库链接：http://downloads.mysql.com/docs/world.sql.zip

这是我到目前为止所做的触发器

DELIMITER $$
CREATE TRIGGER deleteonlanguage
AFTER DELETE ON city
FOR EACH ROW
BEGIN
IF (old.countrycode IN (SELECT countrycode FROM countrylanguage WHERE Percentage < 75 AND LANGUAGE LIKE "english"))
THEN signal SQLSTATE '45000' 
SET message_text = "You cannot delete this city as the total language percentage is less than 75 or is English";

END IF;
END $$
DELIMITER ;;

希望我可以在此方面获得一些帮助，因为我仍然是SQL noob，谢谢！