Question

我正在使用SQL Server 2008.我已经为客户进行了销售，我希望将其与前一年客户购买的产品进行比较，并计算增长。一切正常，但一旦客户在其中一个月内出现负数，它就会为Target＆amp;增长。

Customer     SalesLastYearMonth      SalesThisYearMonth      Target     Growth
------------------------------------------------------------------------------
abcd         -1                      15                      ????       ???

代码：

SELECT
    Customer,
    CASE 
        WHEN SalesThisYearMonth IS NULL THEN (SalesLastYearMonth * -1)
        WHEN SalesLastYearMonth IS NULL THEN SalesThisYearMonth 
        ELSE SalesThisYearMonth -  SalesLastYearMonth END as Target,
    CASE 
        WHEN SalesThisYearMonth IS NULL THEN -1 
        WHEN SalesLastYearMonth IS NULL THEN 1 
        WHEN SalesThisYearMonth = 0 then -1
        WHEN SalesLastYearMonth = 0 then 1
        ELSE ( SalesThisYearMonth - SalesLastYearMonth) / SalesLastYearMonth END AS Growth

Answer 1

假设您想要TARGET = 16，GROWTH = 16，那么应该这样做：

SELECT
    Customer,
    CASE 
        WHEN SalesThisYearMonth IS NULL THEN (SalesLastYearMonth * -1)
        WHEN SalesLastYearMonth IS NULL THEN SalesThisYearMonth 
        ELSE SalesThisYearMonth -  SalesLastYearMonth END as Target,
    CASE 
        WHEN SalesThisYearMonth IS NULL THEN -1 
        WHEN SalesLastYearMonth IS NULL THEN 1 
        WHEN SalesThisYearMonth = 0 then -1
        WHEN SalesLastYearMonth = 0 then 1
        ELSE ( SalesThisYearMonth - SalesLastYearMonth) / ABS(SalesLastYearMonth) END AS Growth

但是，我真的不确定那里的成长 - 不确定为什么要除以SalesLastYearMonth。在上面的情况下这是有效的，但如果SalesLastYearMonth为-4，除以4你想要的是什么？

Answer 2

您要除以负数：

SalesLastYearMonth = -1

您需要检查它或返回绝对值。

Answer 3

只是一个小小的建议。尝试使用ISNULL（）函数。如果您选择的值为NULL，则可以给出默认返回值。据我所知，它比CASE WHEN快得多。

总和负数和正数

3 个答案: