创建一个＆＃39; if＆＃39;在MySQL中触发

Question

我试图创建一个仅在满足条件时才会运行的触发器。

create trigger t_free 
before insert on vacation_days
for each row 
if new.days_newtier>= 365 
then set new.free=new.days_CurrYear*(select a.rate 
from algorithm a where new.work_days between a.day1 and a.day2);

我一直收到语法错误。没有if语句，触发器工作正常。