select T.BILL_CODE,t.SCAN_TYPE,t.PIECE,SCAN_SITE,SCAN_MAN,
row_number() over(partition by t.bill_code order by t.scan_date desc) AS R from tab_scan_send t
语法: rank() over (order by 排序字段 顺序) rank() over (partition by 分组字段 order by 排序字段 顺序) --已知:两种排名方式(分区和不分区):使用和不使用partition --两种计算方式(连续,不连续),对应函数:dense_rank,rank, row_number()