mysql trigger里怎么修改表自身？

Question

MYSQL触发器如下 ：

···
CREATE TRIGGER REPLY_COUNT AFTER INSERT ON ARTICLE_COMMENT FOR EACH ROW
BEGIN
UPDATE ARTICLES SET COMMENT_COUNT=COMMENT_COUNT+1 WHERE ID=NEW.ARTICLE_ID LIMIT 1;
IF NEW.TYPE='REPLY' THEN
UPDATE ARTICLE_COMMENT SET REPLY_COUNT=REPLY_COUNT+1 WHERE ID=NEW.REPLYTO LIMIT 1;
END IF;
END$;
···
网上説mysql触发器不允许修改表自身。请问我该怎么写？