Oracle 计算涉及另一个计算的结果

Question

首先，尽管我对 SQL 非常熟悉，但我完全是 Oracle 菜鸟。我有一个成本列。我需要计算总成本，总成本的百分比，然后是百分比的运行总和。我在百分比的运行总和方面遇到了麻烦，因为我能想到的唯一方法是使用嵌套的 SUM 函数，这是不允许的。

以下是有效的:

SELECT cost, SUM(cost) OVER() AS total, cost / SUM(cost) OVER() AS per
FROM my_table
ORDER BY cost DESC

这是我尝试做的但不起作用:

SELECT cost, SUM(cost) OVER() AS total, cost / SUM(cost) OVER() AS per,
       SUM(cost/SUM(cost) OVER()) OVER(cost) AS per_sum
FROM my_table
ORDER BY cost DESC

我只是做错了，还是我试图做的事情不可能？顺便说一句，我使用的是 Oracle 10g。提前感谢您的帮助。

Answer 1

您不需要在该内联 View 中进行排序，尤其是因为外部选择正在按顺序进行排序。另外，cost/SUM(cost) OVER () 等于 RATIO_TO_REPORT(cost) OVER ()。

一个例子:

SQL> create table my_table(cost)
  2  as
  3  select 10 from dual union all
  4  select 20 from dual union all
  5  select 5 from dual union all
  6  select 50 from dual union all
  7  select 60 from dual union all
  8  select 40 from dual union all
  9  select 15 from dual
 10  /

Table created.

您的初始查询:

SQL> SELECT cost, SUM(cost) OVER() AS total, cost / SUM(cost) OVER() AS per
  2  FROM my_table
  3  ORDER BY cost DESC
  4  /

      COST      TOTAL        PER
---------- ---------- ----------
        60        200         .3
        50        200        .25
        40        200         .2
        20        200         .1
        15        200       .075
        10        200        .05
         5        200       .025

7 rows selected.

Quassnoi 的查询包含一个错字:

SQL> SELECT  cost, total, per, SUM(running) OVER (ORDER BY cost)
  2  FROM    (
  3          SELECT  cost, SUM(cost) OVER() AS total, cost / SUM(cost) OVER() AS per
  4          FROM    my_table
  5          ORDER BY
  6                  cost DESC
  7          )
  8  /
SELECT  cost, total, per, SUM(running) OVER (ORDER BY cost)
                              *
ERROR at line 1:
ORA-00904: "RUNNING": invalid identifier

如果我纠正了那个错字。它给出了正确的结果，但排序错误(我猜):

SQL> SELECT  cost, total, per, SUM(per) OVER (ORDER BY cost)
  2  FROM    (
  3          SELECT  cost, SUM(cost) OVER() AS total, cost / SUM(cost) OVER() AS per
  4          FROM    my_table
  5          ORDER BY
  6                  cost DESC
  7          )
  8  /

      COST      TOTAL        PER SUM(PER)OVER(ORDERBYCOST)
---------- ---------- ---------- -------------------------
         5        200       .025                      .025
        10        200        .05                      .075
        15        200       .075                       .15
        20        200         .1                       .25
        40        200         .2                       .45
        50        200        .25                        .7
        60        200         .3                         1

7 rows selected.

我想这就是你要找的那个:

SQL> select cost
  2       , total
  3       , per
  4       , sum(per) over (order by cost desc)
  5    from ( select cost
  6                , sum(cost) over () total
  7                , ratio_to_report(cost) over () per
  8             from my_table
  9         )
 10   order by cost desc
 11  /

      COST      TOTAL        PER SUM(PER)OVER(ORDERBYCOSTDESC)
---------- ---------- ---------- -----------------------------
        60        200         .3                            .3
        50        200        .25                           .55
        40        200         .2                           .75
        20        200         .1                           .85
        15        200       .075                          .925
        10        200        .05                          .975
         5        200       .025                             1

7 rows selected.

问候，抢。