同一分区上的多个窗口函数

Question

这很好用：

SUM(Revenue) OVER (PARTITION BY Year) AS TotalRevenue

我该如何做到这一点？

SUM(Revenue) - SUM(Cost) OVER (PARTITION BY Year) AS TotalProfit

换句话说，它可以让两个或多个窗口函数进行交互吗？

Answer 1

这是一种方式：

SUM(Revenue - Cost) OVER (PARTITION BY Year) AS TotalProfit

或者：

SUM(Revenue) OVER (PARTITION BY YEAR) - SUM(Cost) OVER (PARTITION BY YEAR) as TotalProfit

这些不完全相同 - 由于NULL值，两者都可能会关闭。可能最安全的方法是：

SUM(COALESCE(Revenue, 0) - COALESCE(Cost, 0)) OVER (PARTITION BY Year) AS TotalProfit