SELECT * FROM( SELECT orderid,createtime, ROW_NUMBER() over(PARTITION by orderid order by createtime desc) num FROM dbo.yborder_ordernotes WHERE orderid IN ( SELECT id FROM yborder_order WHERE state =10 ) ) tbl WHERE tbl.num=1
sqlserver巧用row_number和partition by分组取top数据
原文：http://www.cnblogs.com/panqingqiang/p/5120483.html