为什么这个mysql触发器语法是错误的?

Why is this mysql trigger syntax is wrong?

本题涉及两个表:Register(eid, sid, price, rating)和Event(eid, ename, edescription, edate, memprice, nonmemprice, maxpeople)。

我想创建一个触发器来监控注册,如果任何活动的注册人数超过此类活动允许的最大人数的 80%,我们就会将此活动的非会员价格提高 50% .

到目前为止我有这样的东西

delimiter//
create trigger price_change 
after insert on Register for each row begin
      DECLARE counts INT;
      DECLARE maxpeople INT;
      set counts = (select count(sid) from Register
                   JOIN Event ON Register.eid = Event.eid
                   where eid = new.eid);
      set maxpeople = (select maxpeople from Event where Event.eid = 
                       new.eid);
      if counts >= 0.8 * maxpeople
      then
          update Event set nonmemprice = nonmemprice * 1.5 where eid 
          = new.eid;
      end if;
end//

delimiter;

我还在学习如何编写触发器,最后我得到了这个触发器。我试图将它添加到 MySQL 中,但它说这个触发器基本上到处都有语法错误。我真的很困惑。如果有人帮助我,我将不胜感激。

错误就在开头。在两者之间使用 space:

delimiter //
         ^--------------here

当然最后也是:delimiter ;