映射时忽略null或Optional.empty值

Question

是否可以映射此内容，而不是遍历它？ 在某些情况下，不应将值放在地图中，因此我想忽略这些情况：

WITH ncte AS (
    SELECT CustomerName
         , SUM(TotalSales) AS CustomerTotal
         , SUM(SUM(TotalSales)) OVER () AS GrandTotal
         , ROW_NUMBER() OVER (ORDER BY SUM(TotalSales) DESC) AS RN
    FROM customers
    GROUP BY CustomerName
), rcte AS (
    SELECT base.CustomerName
         , base.CustomerTotal
         , base.GrandTotal
         , base.RN
         , base.CustomerTotal AS RunningTotal
         , 1 AS CL
    FROM ncte AS base
    WHERE base.RN = 1
    UNION ALL
    SELECT curr.CustomerName
         , curr.CustomerTotal
         , curr.GrandTotal
         , curr.RN
         , IIF(prev.RunningTotal < CHOOSE(prev.CL, .4, .3, .2, .1) * prev.GrandTotal, prev.RunningTotal, 0) + curr.CustomerTotal
         , IIF(prev.RunningTotal < CHOOSE(prev.CL, .4, .3, .2, .1) * prev.GrandTotal, prev.CL, prev.CL + 1)
    FROM ncte AS curr
    JOIN rcte AS prev ON curr.RN = prev.RN + 1
)
SELECT *
FROM rcte