sql - 获取每个 Group By SQL 的最新记录

Question

我有下表:

-----------------------------------------------------------
ID     oDate         oName     oItem    oQty    oRemarks
-----------------------------------------------------------
1      2016-01-01    A         001      2       
2      2016-01-01    A         002      1       test
3      2016-01-01    B         001      3  
4      2016-01-02    B         001      2
5      2016-01-02    C         001      2
6      2016-01-03    B         002      1
7      2016-01-03    B         001      4
       ff.

我想获取每个名称的最新记录。所以结果应该是这样的:

-----------------------------------------------------------
oDate         oName     oItem    oQty    oRemarks
-----------------------------------------------------------
2016-01-01    A         001      2       
2016-01-01    A         002      1       test
2016-01-02    C         001      2
2016-01-03    B         002      1
2016-01-03    B         001      4
ff.

有谁知道如何得到这个结果？

Answer 1

rank window 子句允许您根据某些分区对行进行排名，然后您可以只选择顶部的行:

SELECT oDate, oName, oItem, oQty, oRemarks
FROM   (SELECT oDate, oName, oItem, oQty, oRemarks,
               RANK() OVER (PARTITION BY oName ORDER BY oDate DESC) AS rk
        FROM   my_table) t
WHERE  rk = 1