sql 服务器的三天滚动平均值

Question

我想找到三天的平均值。预期输出：

dt	amt	running_avg
2022-05-1	100	0
2022-05-2	150	0
2022-05-3	50	100
2022-05-14	250	150
2022-05-15	0	100

应计算 3 天的平均值 window。我的查询是：

select a.dt, avg(b.amt) over(order by a.dt ) as running_avg,b.amt
from trans a
left join trans b on b.dt = a.dt
where a.dt between DATEADD(day,-3, a.dt) and getdate()

我的查询只是给出正常的运行平均值，而不是 3 天的平均值。让我知道如何在 SQL 服务器中完成此操作。

谢谢！

Answer 1

您似乎需要 ROWS/RANGE 窗口中的参数 AVG():

数据：

SELECT *
INTO trans
FROM (VALUES
   (CONVERT(date, '20220501'), 100),
   (CONVERT(date, '20220502'), 150),
   (CONVERT(date, '20220503'), 50),
   (CONVERT(date, '20220514'), 250),
   (CONVERT(date, '20220515'), 0)
) v (dt, amt)

声明：

SELECT 
   dt, 
   amt,
   AVG(amt) OVER (ORDER BY dt ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) AS running_avg,
   CASE WHEN COUNT(*) OVER (ORDER BY dt ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) = 3 
      THEN AVG(amt) OVER (ORDER BY dt ROWS BETWEEN 2 PRECEDING AND CURRENT ROW)
      ELSE 0
   END AS running_avg2
FROM trans
ORDER BY dt

结果：

dt	amt	running_avg	running_avg2
2022-05-01	100	100	0
2022-05-02	150	125	0
2022-05-03	50	100	100
2022-05-14	250	150	150
2022-05-15	0	100	100

sql 服务器的三天滚动平均值

rolling three day average in sql server

sql

sql-server