触发器 如何判断是 插入触发的，还是更新触发的

if exists (select 1 from inserted) and not exists (select 1 from deleted)
    --insert

if exists (select 1 from inserted) and exists (select 1 from deleted)
    --update

if not exists (select 1 from inserted) and exists (select 1 from deleted)
    --delete