如何在 select 语句中包含 PERCENTILE_CONT 列而不产生关于 ORDER BY 子句或聚合函数的错误？

Question

我需要根据一些数据生成特定的报告，但我在确定 PERCENTILE_CONT 的正确用法以提供我需要的结果时遇到了很多麻烦。我想在我的查询结果中包含一个列，它显示某个值范围的第 95 个百分位数是什么值。

我有一个table如下：

customer_id sale_amount sale_date
1   265.75  2019-09-11 00:00:04.000
1   45.75   2019-09-10 01:00:04.000
1   2124.77 2019-09-10 04:00:04.000
1   66.99   2019-09-10 04:20:04.000
1   266.49  2019-09-09 11:20:04.000
1   3266.49 2019-09-08 11:20:04.000

非常简单。

我可以运行下面的查询，没问题:

select min(sale_amount) as minimum_sale, max(sale_amount) as maximum_sale, avg(sale_amount) as average_sale from sales where customer_id = 1;

结果如下：

minimum_sale    maximum_sale    average_sale
45.75           3266.49     1006.040000

我要查找的是第四列 perc_95，它将根据 sale_amount.

计算代表第 95 个百分位数的值

这可以让我得到价值：

select distinct customer_id, percentile_cont(0.95) WITHIN GROUP (order by sale_amount) OVER (partition by customer_id) as perc_95 from sales;

输出：

customer_id perc_95
1            2981.06

但我似乎无法将它们组合起来 - 这失败了：

select distinct(customer id), min(sale_amount) as minimum_sale, max(sale_amount) as maximum_sale,
 avg(sale_amount) as average_sale, percentile_cont(0.95) WITHIN GROUP (order by sale_amount) OVER (partition by customer_id) as perc_95
  from sales where customer_id = 1;

输出：

列 'sales.customer_id' 在 select 列表中无效，因为它未包含在聚合函数或 GROUP BY 子句中。

我大体上理解这个错误的含义，但我无法弄清楚在这种情况下如何处理它。

我想要的输出：

customer_id     minimum_sale      maximum_sale  average_sale    perc_95
1                   45.75         3266.49  1006.040000     2981.06

Answer 1

使用window个函数：

select distinct customer_id,
       min(sale_amount) over (partition by customer_id) as minimum_sale, 
       max(sale_amount) over (partition by customer_id) as maximum_sale,
       avg(sale_amount) over (partition by customer_id) as average_sale,
       percentile_cont(0.95) within group (order by sale_amount)  over (partition by customer_id) as perc_95
from sales
where customer_id = 1;

非常不方便SQL服务器不支持percentile_cont()等功能作为聚合功能，需要大家使用select distinct用于聚合。

Answer 2

不要使用 DISTINCT。

我会先尝试这个：

select 
    min(customer_id) AS CustomerID, 
    min(sale_amount) as minimum_sale, 
    max(sale_amount) as maximum_sale,
    avg(sale_amount) as average_sale, 
    percentile_cont(0.95) WITHIN GROUP (order by sale_amount) OVER (partition by customer_id) as perc_95
from sales 
where customer_id = 1;

如果您收到相同的错误消息，但这次是关于 percentile_cont，那么也将其包装在 min 函数中：

select 
    min(customer_id) AS CustomerID, 
    min(sale_amount) as minimum_sale, 
    max(sale_amount) as maximum_sale,
    avg(sale_amount) as average_sale, 
    min(percentile_cont(0.95) WITHIN GROUP (order by sale_amount) OVER (partition by customer_id)) as perc_95
from sales 
where customer_id = 1;

如何在 select 语句中包含 PERCENTILE_CONT 列而不产生关于 ORDER BY 子句或聚合函数的错误？

How can I include a PERCENTILE_CONT column within a select statement without generating an error about the ORDER BY clause or aggregate function?

sql

sql-server

percentile-cont