Oracle SQL Identify Siblings via siblings 并计算相对比例

Question

我有一组相关记录及其相关比率。不幸的是，并不是所有的比率都被捕获，而是它们可以从其他比率中导出。正如我可能需要 A -> D 的比率，但我没有直接的比率来参考，但我可以从下面的示例中通过 A->C (0.5) 的比率和 C-> 的比率得出它D (3) 因此 0.5 * 3 = 1.5。或者我可以通过反转 A->B (1/2 = 0.5) 的比率得出 B，然后取 A->C (0.5) 的比率 (1/2) * 0.5 = 0.25 等等.

例如

FROM_UNIT_ID  TO_UNIT_ID  RATIO
A             B           2
A             C           0.5
C             D           3

我想要做的是计算所有可能路径及其比率的完整列表，如下所示。

FROM_UNIT_ID  TO_UNIT_ID  RATIO
A             B           2
A             C           0.5
C             D           3
A             D           1.5
B             C           0.25
B             D           0.75
B             A           0.5
C             A           2
C             B           4
D             A           0.666666667
D             B           1.333333333
D             C           0.333333333

使用以下我已经能够推导出一个口粮的所有兄弟以获得可能路径的列表，但我无法调整此查询来计算比率。我正在使用 Oracle 11g。

SELECT
       CONNECT_BY_ROOT( FROM_UNIT_ID ) AS FROM_UNIT_ID,
       TO_UNIT_ID
FROM   (
  SELECT FROM_UNIT_ID, TO_UNIT_ID, RATIO FROM RATIOS 
  UNION
  SELECT TO_UNIT_ID, UNIT_ID, 1/RATIO AS RATIO FROM RATIOS 
)
WHERE  CONNECT_BY_ROOT( FROM_UNIT_ID ) <> TO_UNIT_ID
CONNECT BY NOCYCLE
       PRIOR TO_UNIT_ID = FROM_UNIT_ID
ORDER BY FROM_UNIT_ID, TO_UNIT_ID;

Answer 1

在 Oracle 11.2 及更高版本中（递归 WITH 子句可用），您可以这样做（假设输入 table 中的数据不自相矛盾）：

with
  test_data (from_unit_id, to_unit_id, ratio) as (
    select 'A', 'B', 2   from dual union all
    select 'A', 'C', 0.5 from dual union all
    select 'C', 'D', 3   from dual
  )
, symm_data (x, y, r) as (
    select case when h.source = 1 then from_unit_id else to_unit_id   end,
           case when h.source = 1 then to_unit_id   else from_unit_id end,
           case when h.source = 1 then ratio        else 1/ratio      end
    from   test_data cross join 
                     (select 1 as source from dual union all select 2 from dual) h
  )
, all_nodes (x) as (
    select distinct x
    from   symm_data
  )
, rec (x, y, r) as (
    select x, x, 1
      from all_nodes
    union all
    select r.x, s.y, r.r * s.r
      from rec r join symm_data s on r.y = s.x
  )
  cycle x, y set cycle to 'Y' default 'N'
select x as from_unit_id, y as to_unit_id, round(r, 4) as ratio 
from   rec
where  cycle = 'N' and x != y
order  by x, y
;

输出：

FROM_UNIT_ID TO_UNIT_ID        RATIO
------------ ------------ ----------
A            B                     2
A            C                    .5
A            D                   1.5
B            A                    .5
B            C                   .25
B            D                   .75
C            A                     2
C            B                     4
C            D                     3
D            A                 .6667
D            B                1.3333
D            C                 .3333

注意 - 我在最后的 SELECT 中使用了 ROUND；通常它应该只在最终报告中使用，否则你不应该在任何地方四舍五入。

Answer 2

您可以通过计算所有个体的值来做到这一点 unit_ids 假设其中之一为 1，然后用它来计算比率：

--Creating the sample table

Create table ratios as
(select 'A' as FROM_UNIT_ID,'B' as  TO_UNIT_ID,cast(2 as float) as  RATIO from dual union
select 'A','C',0.5 from dual union
select 'C', 'D',3 from dual);

--Creating a list of unique unit_ids

Create table unit_id as
select a.*,CAST(NULL as float) as Val from
(select distinct from_unit_id as unit_id from ratios
UNION
select distinct to_unit_id as unit_id from ratios)a;

--Updating the first value to be 1

UPDATE unit_id
SET Val=1
WHERE rownum=1;

--Updating the other values based on the known values

UPDATE unit_id
SET Val=
(select Calc from 
(Select a.Unit_ID,c.Val*b.ratio as Calc
FROM unit_id a
INNER JOIN ratios b on a.unit_id=b.to_unit_id
INNER JOIN unit_id c on c.unit_id=b.from_unit_id) b 
WHERE Unit_ID.Unit_Id=b.Unit_Id)
WHERE Unit_ID.Val is null;

--Updating the other values based on the known values
--You can repeat this step a couple more times if needed

UPDATE unit_id
SET Val=
(select Calc from 
(Select a.Unit_ID,c.Val*b.ratio as Calc
FROM unit_id a
INNER JOIN ratios b on a.unit_id=b.to_unit_id
INNER JOIN unit_id c on c.unit_id=b.from_unit_id) b 
WHERE Unit_ID.Unit_Id=b.Unit_Id)
WHERE Unit_ID.Val is null;

select a.Unit_id as from_unit_id,
      b.unit_id as to_unit_id,
      trunc(a.val/b.val,2) as ratio
from unit_id a
cross join unit_id b
where a.unit_id<>b.unit_id
order by a.unit_id,b.unit_id

希望对您有所帮助。

Oracle SQL Identify Siblings via siblings 并计算相对比例

Oracle SQ Identify Siblings via siblings and calculate related ratio

sql

oracle

plsql

oracle11g

graph-algorithm