用CASE求和..防止被零除

Question

我的查询：

SELECT 
UPC,
SUM(
        CASE WHEN WEEK <= 13 THEN COST_AMOUNT ELSE 0 END
) /
SUM(
        CASE WHEN WEEK <= 13 THEN COST_QUANTITY ELSE 0 END
)

返回零除，因为如果upc没有WEEK <= 13数据，则除数将为零。

我有此解决方案，但我需要为多个日期范围创建平均值，这似乎有点长。

SELECT
UPC,
SUM(
    CASE WHEN WEEKS <= 13 
    THEN Cost_Amount 
    ELSE 0 END
) /
CASE WHEN 
    SUM(
        CASE WHEN WEEKS<=13 
        THEN Cost_Quantity 
        ELSE 0 END
    )=0 
THEN 1 
ELSE SUM(
        CASE WHEN WEEKS<=13 
        THEN Cost_Quantity 
        ELSE 0 END
    )
END

Answer 1

只需删除分母中的else ：

SELECT UPC,
       (SUM(CASE WHEN WEEK <= 13 THEN COST_AMOUNT ELSE 0 END) /
        SUM(CASE WHEN WEEK <= 13 THEN COST_QUANTITY END)
       )

这将返回NULL而不是错误。 如果要在这种情况下获取特定值，可以使用COALESCE() 。

Answer 2

您可以尝试分手查询-

SELECT 
    UPC, 
    SUM_COST_AMOUNT / DECODE(SUM_COST_QTY,0,1,SUM_COST_QTY)
FROM 
(
    SELECT 
        UPC,
        SUM(
            CASE WHEN WEEK <= 13 THEN COST_AMOUNT ELSE 0 END
            ) AS SUM_COST_AMOUNT, 
        SUM(
            CASE WHEN WEEK <= 13 THEN COST_QUANTITY ELSE 0 END
            ) AS SUM_COST_QTY
    FROM .. 
    ..
    ..
    ..
)