我需要在移动时间窗口内对值进行排名。我参考了Tony Hasler的博客文章,
https://tonyhasler.wordpress.com/2012/10/24/model-clause-use-cases/#comment-5116,但是为非窗口函数添加窗口化子句(如中位数)的解决方案不适用于排名(rank())或百分比排名(percent_rank())函数,这些函数是分析型的非窗口函数。
下面是使用median()函数的工作示例:
下面是使用median()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
;
如果我们将中位数替换为rank(),则示例将无法正常工作,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 * 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
;
我很感激您的帮助。
谢谢。