如何使用 Oracle SQL 将移动窗口添加到 rank()

Posted 2023-03-31

【中文标题】如何使用 Oracle SQL 将移动窗口添加到 rank()

【英文标题】：How do I add a moving window to rank() using Oracle SQL

【发布时间】：2014-09-05 13:05:04

【问题描述】：

我需要在移动的时间窗口内对值进行排名。我从 Tony Hasler 的一篇博文中得到了一些指导 https://tonyhasler.wordpress.com/2012/10/24/model-clause-use-cases/#comment-5116 但是将窗口子句添加到非窗口函数（如中位数）的解决方案不适用于作为分析非窗口函数的 rank() 或 percent_rank() 函数。

具有中值（）函数的工作示例：

with a as (
    select 'a' sector, trunc(sysdate) dt, 64 v from dual union all
    select 'a' sector, trunc(sysdate)-1 dt, 2 from dual union all
    select 'a' sector, trunc(sysdate)-2 dt, 4 from dual union all
    select 'a' sector, trunc(sysdate)-3 dt, 128 from dual union all
    select 'a' sector, trunc(sysdate)-4 dt, 8 from dual union all
    select 'a' sector, trunc(sysdate)-5 dt, 16 from dual union all
    select 'a' sector, trunc(sysdate)-6 dt, 32 from dual union all
    select 'a' sector, trunc(sysdate)-7 dt, 256 from dual union all
    select 'a' sector, trunc(sysdate)-8 dt, 1 v from dual union all
    select 'a' sector, trunc(sysdate)-9 dt, 512 from dual union all
    select 'b' sector, trunc(sysdate) dt, 3 from dual union all
    select 'b' sector, trunc(sysdate)-1 dt, 27 from dual union all
    select 'b' sector, trunc(sysdate)-2 dt, 9 from dual union all
    select 'b' sector, trunc(sysdate)-3 dt, 81 from dual 
)
select * from a
model
partition by (sector)
dimension by (dt)
measures (v, 0 mov_rank)
rules 
(
    mov_rank[ANY] = median(v)[dt between CV()-3 and CV()]
)
order by sector, dt
;

如果我们用 rank() 替换中位数，则示例不起作用，如下所示：

with a as (
    select 'a' sector, trunc(sysdate) dt, 64 v from dual union all
    select 'a' sector, trunc(sysdate)-1 dt, 2 from dual union all
    select 'a' sector, trunc(sysdate)-2 dt, 4 from dual union all
    select 'a' sector, trunc(sysdate)-3 dt, 128 from dual union all
    select 'a' sector, trunc(sysdate)-4 dt, 8 from dual union all
    select 'a' sector, trunc(sysdate)-5 dt, 16 from dual union all
    select 'a' sector, trunc(sysdate)-6 dt, 32 from dual union all
    select 'a' sector, trunc(sysdate)-7 dt, 256 from dual union all
    select 'a' sector, trunc(sysdate)-8 dt, 1 v from dual union all
    select 'a' sector, trunc(sysdate)-9 dt, 512 from dual union all
    select 'b' sector, trunc(sysdate) dt, 3 from dual union all
    select 'b' sector, trunc(sysdate)-1 dt, 27 from dual union all
    select 'b' sector, trunc(sysdate)-2 dt, 9 from dual union all
    select 'b' sector, trunc(sysdate)-3 dt, 81 from dual 
)
select * from a
model
partition by (sector)
dimension by (dt)
measures (v, 0 mov_rank)
rules 
(
    mov_rank[ANY] = rank() over (order by v)[dt between CV()-3 and CV()]
)
order by sector, dt
;

我将不胜感激。

谢谢。

【参考方案1】：

这可能有点“过时”，但您可以使用自联接而不是分析或model 来获得等效结果，例如：

with a as (
    select 'a' sector, trunc(sysdate) dt, 64 v from dual union all
    select 'a' sector, trunc(sysdate)-1 dt, 2 from dual union all
    select 'a' sector, trunc(sysdate)-2 dt, 4 from dual union all
    select 'a' sector, trunc(sysdate)-3 dt, 128 from dual union all
    select 'a' sector, trunc(sysdate)-4 dt, 8 from dual union all
    select 'a' sector, trunc(sysdate)-5 dt, 16 from dual union all
    select 'a' sector, trunc(sysdate)-6 dt, 32 from dual union all
    select 'a' sector, trunc(sysdate)-7 dt, 256 from dual union all
    select 'a' sector, trunc(sysdate)-8 dt, 1 v from dual union all
    select 'a' sector, trunc(sysdate)-9 dt, 512 from dual union all
    select 'b' sector, trunc(sysdate) dt, 3 from dual union all
    select 'b' sector, trunc(sysdate)-1 dt, 27 from dual union all
    select 'b' sector, trunc(sysdate)-2 dt, 9 from dual union all
    select 'b' sector, trunc(sysdate)-3 dt, 81 from dual 
)
select
    a.sector, 
    a.dt, 
    a.v, 
    count(case when self.v < a.v then self.v end) + 1 mov_rank
from
    a,
    a self
where
    self.sector = a.sector
    and
    self.dt between a.dt - 3 and a.dt + 3
group by 
    a.sector, 
    a.dt, 
    a.v
order by 
    a.sector, 
    a.dt, 
    a.v;