mysql-Mysql数据库触发器执行不成功

相关mysql视频教程推荐：《mysql教程》

• Mysql数据库中有order、orderitem和goods三张表，其中order与orderitem通过order的ID字段与orderitem的orderid字段关联；其中goods与orderitem通过goods的ID字段与orderitem的goodsid字段关联；

• 现在想做一个触发器，当一个订单被确认的时候，该订单中所有产品的剩余数量和出售数量做相应的改变，order表isvalid字段的值有其他值变为Y的时候更新goods表中store和salecount值，请问写入下的触发器为什么不能实现目的呢，另外在脚本中提示已经创建成功怎么通过SELECT * FROM information_schema.TRIGGERS;查询不到触发器呢？

• delimiter ||
  drop trigger if exists updatestore||
  create trigger updatestore after update on order for each row
  begin
   declare numorder int(11);
   set numorder = (select count(count) from orderitem where orderid = old.id);
   if new.isvalid ='Y' and old.isvalid !='Y' then
    update goods set store = store - @numorder, salecount = salecount + @numorder where id in (select goodsid from zsorderitem where orderid = old.id);
   end if;
   if new.isvalid !='Y' and old.isvalid ='Y' then
    update goods set store = store + @numorder, salecount = salecount - @numorder where id in (select goodsid from orderitem where orderid = old.id);
   end if;
  end||