Sql函数，窗口函数，求解答

怎么把查看顾客上次购买时间的窗口函数：
select name,orderdate,cost,lag(orderdate,1,'1900-01-01') over(partition by name order by orderdate) as time1, lag(orderdate,2) over (partition by name order by orderdate) as time2 from business;
不用窗口函数写出来？求指教

order by orderdate desc limit 1;可以不？