如何在明细项目中分配 header 级折扣

Question

我有 2 tables，header 和细节。如下所示，header table 将有 1 条记录，详细信息 table 将有多条记录。现在 header 级别有折扣。我想按重量分配每个细节项目的折扣并获得实际费率。

谢谢。

Answer 1

您需要根据 (rate * qty) 占交易总额的百分比来分配折扣：

WITH transaction_totals AS (

    SELECT   h.header_id
            ,h.discount
            ,SUM(d.rate * d.ty) AS total
    FROM header h
        INNER JOIN detail d
            ON h.header_id = d.header_id
    GROUP BY h.header_id
            ,h.discount

)

SELECT   d.item
        ,d.rate
        ,d.qty
        ,d.total
        --,d.total / tt.total AS DetailPctTotal
        ,tt.discount * (d.total / tt.total) AS DetailDiscount
FROM detail d
    INNER JOIN transaction_totals tt
        ON d.header_id = tt.header_id
;