面板数据sql移动平均线

Question

我有这些数据：

id	Date	postal code	Type	price	AVG price
1045	01/01/2020	75011	flat	100
1046	01/02/2020	75011	flat	125
1047	01/03/2020	75011	flat	150
1048	01/01/2020	75011	house	200
1049	01/02/2020	75011	house	300
1050	01/03/2020	75011	house	400
1051	01/01/2020	75012	.....	.....

我想要 3 个或更多周期的移动平均线，我得到类似的结果：

id	Date	postal code	Type	price	AVG price
1045	01/01/2020	75011	flat	100	100
1046	01/02/2020	75011	flat	125	112,5
1047	01/03/2020	75011	flat	150	125
1048	01/01/2020	75011	house	200	158,33
1049	01/02/2020	75011	house	300	216,66
1050	01/03/2020	75011	house	400	300
1051	01/01/2020	75012	.....	.....

但我希望它能给我一些在类型和价格发生变化时重新开始的东西：

id	Date	postal code	Type	price	AVG price
1045	01/01/2020	75011	flat	100	100
1046	01/02/2020	75011	flat	125	112,5
1047	01/03/2020	75011	flat	150	125
1048	01/01/2020	75011	house	200	200
1049	01/02/2020	75011	house	300	250
1050	01/03/2020	75011	house	400	300
1051	01/01/2020	75012	.....	.....

现在我的要求是这样的

select ID, date, postal_code, type, price, 
      AVG(price) OVER(ORDER by "date"::date ROWS BETWEEN 3 PRECEDING AND CURRENT ROW)AS avg_price 
from x

Answer 1

你可以试试这个：

SELECT ID, date, postal_code, type, price, 
       avg(price) OVER (PARTITION BY type ORDER BY "date"::date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
  FROM x