如何获得聚合列的累积和？答案

【问题标题】：How to get the cumulative sum of an aggregate column?如何获得聚合列的累积和？
【发布时间】：2022-01-13 18:40:16
【问题描述】：

我在 BigQuery 中有这个查询，它返回总 contributing_factor_vehicle_1 的表示形式

SELECT
    TBL_TOTAL.contributing_factor_vehicle_1,
    TBL_TOTAL.TOTAL,
    (TBL_TOTAL.TOTAL / SUM(TBL_TOTAL.TOTAL) OVER ()) * 100  AS PERCENTAGE
FROM 
    (SELECT 
         contributing_factor_vehicle_1,
         COUNT(contributing_factor_vehicle_1) AS TOTAL
     FROM 
         `bigquery-public-data.new_york_mv_collisions.nypd_mv_collisions` 
     WHERE 
         borough = 'BROOKLYN' 
         AND contributing_factor_vehicle_1 <> 'Unspecified'
     GROUP BY 
         contributing_factor_vehicle_1
     ORDER BY 
         TOTAL DESC) TBL_TOTAL
ORDER BY 
    TOTAL DESC

输出：

contributing_factor_vehicle_1	TOTAL	PERCENTAGE
Driver Inattention/Distraction	65427	28.913538237178777
Failure to Yield Right-of-Way	25831	11.415250679452903
Backing Unsafely	16384	7.240426895286917
Following Too Closely	12605	5.570408997503148
Passing Too Closely	10875	4.805886382217116

现在我需要获取累积的PERCENTAGE 来进行帕累托分析：请问我该如何实现？是否可以在窗口函数中再次使用PERCENTAGE 列？

contributing_factor_vehicle_1	TOTAL	PERCENTAGE	PERCENTAGE CUM
Driver Inattention/Distraction	65427	28.91%	28.91%
Failure to Yield Right-of-Way	25831	11.42%	40.33%
Backing Unsafely	16384	7.24%	47.57%
Following Too Closely	12605	5.57%	53.14%
Passing Too Closely	10875	4.81%	57.95%

【问题讨论】：

标签： sql google-bigquery window-functions

【解决方案1】：

只需在外部 SELECT 中再添加一行，如下例所示

SELECT
  TBL_TOTAL.contributing_factor_vehicle_1,
  TBL_TOTAL.TOTAL,
  ROUND((TBL_TOTAL.TOTAL/SUM(TBL_TOTAL.TOTAL) OVER ())* 100, 2)  AS PERCENTAGE,
  ROUND(((SUM(TBL_TOTAL.TOTAL) OVER (ORDER BY TOTAL DESC))/SUM(TBL_TOTAL.TOTAL) OVER ())* 100, 2) AS PERCENTAGE_CUM
FROM 
(
    SELECT 
    contributing_factor_vehicle_1,
    COUNT(contributing_factor_vehicle_1) AS TOTAL
    FROM `bigquery-public-data.new_york_mv_collisions.nypd_mv_collisions` 
    WHERE borough = 'BROOKLYN' AND contributing_factor_vehicle_1 <> 'Unspecified'
    GROUP BY contributing_factor_vehicle_1
    ORDER BY TOTAL DESC 
) TBL_TOTAL

ORDER BY TOTAL DESC

有输出

【讨论】：