mysql触发器

问答产品 涉及到言论审核之后可能会改变答案的allow状态，而不会返回任何信号。因此，要在ans表中加入一个触发器。

遇到的问题主要是else if语句总是报错，也没有深究 只是改成了若干个IF...THEN...ENDIF

如下

delimiter //
CREATE TRIGGER t1 AFTER UPDATE ON quiz_answer
FOR EACH ROW
BEGIN
IF new.type='1' THEN
 IF new.allow='no' AND old.allow='yes' THEN
 UPDATE quiz_ask SET answers = answers -1 WHERE id = OLD.to_ask;
 END IF;
 IF new.allow='no' AND old.allow='yfws' THEN
 UPDATE quiz_ask SET answers = answers -1 WHERE id = OLD.to_ask;
 END IF;
 IF new.allow='yes' AND old.allow='no' THEN
 UPDATE quiz_ask SET answers = answers +1 WHERE id = OLD.to_ask;
 END IF;
 IF new.allow='yes' AND old.allow='wfws' THEN
 UPDATE quiz_ask SET answers = answers +1 WHERE id = OLD.to_ask;
 END IF;
END IF;
END;
//

触发器是个好东西 ，增加了一种此类问题的解决思路