如何在 select 语句中包含 PERCENTILE_CONT 列而不生成有关 ORDER BY 子句或聚合函数的错误？

Question

我需要从一些数据生成特定的报告，并且在弄清楚 PERCENTILE_CONT 的正确用法以提供我需要的结果时遇到了很大的麻烦。我想在查询结果中包含一列，该列显示一系列值中第 95 个百分位的值。

我有一个表如下：

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。

我可以运行以下查询，没有问题：

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;

这会产生以下输出：

minimum_sale    maximum_sale    average_sale
45.75           3266.49     1006.040000

我想要的是第四列 perc_95，它将计算代表 sale_amount 的第 95 个百分位数的值。

这可以让我获得价值：

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结合起来 - 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”在选择列表中无效，因为它未包含在聚合函数或 GROUP BY 子句中。

我通常理解这个错误的含义，但我无法弄清楚如何在这种情况下处理它。

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

使用窗口函数：

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;

SQL Server不支持聚合percentile_cont()函数等功能，需要人们使用来进行聚合，非常不方便。select distinct