SQL: partition over two columns

问题

I have following table:

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

and I want to sum over partition by both columns (No1,No2) but it should group also when the values are changed in the two columns. Example would be: AB = BA

This would be my expected result:

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

Any ideas?

回答1:

Use least and greatest.

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

回答2:

Just an idea:

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
)
/

Output - you can replace nulls (empty) with any vlue:

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

来源：https://stackoverflow.com/questions/50044809/sql-partition-over-two-columns

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sql

Oracle

window-functions