SQL Server 2012 中的中位数改为 avg() [重复]

Question

我有这个问题

;WITH cte AS
(
    SELECT
        *,
        DATEPART(WEEKDAY, Dt) AS WeekDay,
        PERCENTILE_CONT(0.75) WITHIN GROUP (ORDER BY SaleCount) OVER (PARTITION BY CustomerType, [CustomerName], ItemRelation, DocumentNum, DocumentYear) AS PERCENTILE,
        AVG(SaleCount) OVER (PARTITION BY CustomerType, [CustomerName], ItemRelation, DocumentNum, DocumentYear, DATEPART(WEEKDAY, Dt), IsPromo) AS AVG_WeekDay
    FROM
        promo_data_copy
)
UPDATE a 
SET SaleCount = cte.AVG_WeekDay
FROM CTE
JOIN promo_data_copy a ON a.Dt = cte.dt
                       AND a.ItemRelation = cte.ItemRelation 
                       AND a.CustomerName = cte.CustomerName
                       AND a.DocumentNum = cte.DocumentNum 
                       AND a.DocumentYear = cte.DocumentYear 
                       AND a.CustomerType = cte.CustomerType 
                       AND a.ispromo = cte.ispromo
WHERE 
    CTE.PERCENTILE < CTE.SaleCount
    AND DATEPART(WEEKDAY, CTE.Dt) < 7
    AND CTE.ispromo = 0 ;

这里有字符串

avg(SaleCount) over (Partition by CustomerType, [CustomerName], ItemRelation, DocumentNum, DocumentYear,datePart(WEEKDAY,Dt), IsPromo) as AVG_WeekDay
    From promo_data_copy)

如何计算中位数而不是 avg()？此查询用平均值替换异常值。

我需要用中位数替换它，所以上面的字符串必须代替avg()。

包含中位数（但在 T-SQL 中没有像 Excel 中那样的中位数函数）

有人可以帮忙吗？

Answer 1

您正在寻找PERCENTILE_DISC 或PERCENTILE_CONT：

• https://docs.microsoft.com/en-us/sql/t-sql/functions/percentile-disc-transact-sql?view=sql-server-2017

例如

PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY ...) OVER (PARTITION BY ...) as median