SQL：在两列上分区

Question

我有下表：

---------------------
| No1 | No2  | Amount
---------------------
| A   |  B   |    10 |
| C   |  D   |    20 |
| B   |  A   |    30 |
| D   |  C   |    40 |
---------------------

我想按两列（No1，No2）对分区求和，但当两列中的值发生更改时，它也应该分组。例如：AB = BA

这将是我的预期结果：

-----------------------------------------
| No1 | No2  | Sum(Amount) over partition
-----------------------------------------
| A   |  B   |    40                    |
| C   |  D   |    60                    |
| B   |  A   |    40                    |
| D   |  C   |    60                    |
-----------------------------------------

有什么想法吗？

Answer 1

使用least 和greatest。

select no1,no2,sum(amount) over(partition by least(no1,no2),greatest(no1,no2)) as total
from tbl

Answer 2

只是一个想法：

WITH test_data AS
(
SELECT 'A' no1, 'B' no2, 10 amt FROM dual
UNION ALL
SELECT 'C', 'D', 20 FROM dual
UNION ALL
SELECT 'B', 'A', 30 FROM dual
UNION ALL
SELECT 'D', 'C', 40 FROM dual
)
SELECT NVL(no1, break_group) no1, no2, total --, grp1, grp2, break_group 
  FROM
(
SELECT no1, no2, total
     , grouping(no1) grp1
     , grouping(no2) grp2
     , LAG(no1, 2) OVER (PARTITION BY total ORDER BY no1)||LAG(no1) OVER (PARTITION BY total ORDER BY no1) break_group
  FROM
( -- Vamsi Prabhala query --
select no1, no2
     , sum(amt) over(partition by least(no1,no2),greatest(no1,no2)) as total
from test_data
)
GROUP BY ROLLUP (total, no1, no2)
HAVING grouping(no1) + grouping(no2) = 0
OR grouping(no1) + grouping(no2) = 2
AND total IS NOT NULL
)
/

输出 - 您可以用任何值替换空值（空）：

|NO1 |  NO2  | Total
----------------------
A        B      40
B        A      40
AB              40
C        D      60
D        C      60
CD              60