查找商品的最后售价

Question

我有一张看起来像这样的表

Invoice |Line # |Item # |Price Per
1       |1      |11     |5.00
1       |2      |22     |10.00
2       |1      |11     |5.00
2       |2      |22     |12.00
3       |1      |11     |5.00
4       |1      |11     |6.00

我想获得一件商品的最后售价。

如何运行产生以下结果的脚本？

Invoice |Line # |Item # |Price Per
2       |2      |22     |12.00
4       |1      |11     |6.00

我使用此脚本与当前售价进行比较。

由于

Answer 1

假设invoice和line定义了排序，那么传统方法使用row_number()：

select t.*
from (select t.*,
             row_number() over (partition by item order by invoice desc, line desc) as seqnum
      from t
     ) t
where seqnum = 1;