我想我会用 exists :

update SaleOrder
    set LastModified = @Lastmodified
    where exists (select 1 from inserted i where i.OrderId = SaleOrder.OrderId) or
          exists (select 1 from deleted d where d.OrderId = SaleOrder.OrderId) ;

如果我理解正确的话，这会更好：

UPDATE so
SET LastModified = @LastModified
FROM SaleOrder so
INNER JOIN (SELECT OrderId 
           FROM Inserted 
           UNION
           SELECT OrderId
           FROM Deleted) as t
  ON so.OrderId = t.OrderId

或者另一种方式：

UPDATE SaleOrder
SET LastModified = @LastModified
WHERE OrderId IN (SELECT OrderId 
                  FROM Inserted 
                  UNION
                  SELECT OrderId
                  FROM Deleted)