您将如何实施此查询？ Recordset或Sql

问题描述

| 我在几天前的一次面试中看到了这个问题，下表如下

Region Company Sales ratio_of_sales_in_region  percentile_in_region
 NA     A1      1000            0.25                25
 NA     A2      1000             0.25                50
 NA     A3      1000             0.25                75
 NA     A4      1000             0.25                100 
 EU     B1      2000            0.5                  50
 EU     B2      1000             0.25                75
 EU     B3      1000             0.25                100
.......

我需要提取第30个百分位数的公司和每个地区的销售额 结果将是

Region  30th_percentile_company  30th_percentile_sales
NA           A2                       (1000*0.25 + 500 * 0.05)
EU           B1                        2000    (as B1 accounts for more than 30%)

该查询将需要检查上述条件，例如公司是否已经占了30％以上，并且还考虑了每个区域30％销售额的权重。 编辑：我试图通过添加新列来解释百分位数的含义。我很困惑，但是我看到了询问的结果表，它清楚地表明了第30个百分位数的含义     

解决方法

        

SELECT
   Region,MIN(Company) as [30th_percentile_company],--potentially,two companies would from the same region would have the exact same percentile_in_region.
FROM
(
SELECT
   Region,MIN(percentile_in_region) as percentile_in_region
WHERE
   percentile_in_region > 30
GROUP BY
   Region
) a

INNER JOIN
   TableName T1
ON
   T1.Region = a.Region
   AND T1.percentile_in_region = a.precentile_in_region

GROUP BY
   Region