将除以零时的平均值设为0

Question

我有两个数据库字段（SQL Server），这些字段是十进制的。 SQL Query中的这两个字段都是0我需要占用这些值的百分比。 在此记录中显示数据库错误。 但如果发生这种情况，我需要显示0值。

有一个场景TotalSalesPrice = 0.00＆CurrNewsPrice = 0然后Avgnews公式是AvgNews =（CurrNewsPrice / TotalSalesPrice）* 100

Select  TotalSalesPrice,CurrNewsPrice,CAST(CurrNewsPrice AS decimal(18,2)) / CAST(TotalSalesPrice AS decimal(18,2)) * 100.00 AS AvgNews
from [dbo].[N_NewsLine]

Answer 1

特例呢？

select  TotalSalesPrice,CurrNewsPrice, case
    when TotalSalesPrice = 0 and CurrNewsPrice = 0 then 0
    else CAST(CurrNewsPrice AS decimal(18,2)) /
          CAST(TotalSalesPrice AS decimal(18,2)) * 100.00
    end AS AvgNews
from [dbo].[N_NewsLine]

Answer 2

在分母上使用NULLIF() 。 和ISNULL()的计算结果

Select TotalSalesPrice,
       CurrNewsPrice,
       ISNULL(CAST(CurrNewsPrice AS decimal(18,2)) 
            / CAST(NULLIF(TotalSalesPrice, 0) AS decimal(18,2)) * 100.00, 0) AS AvgNews
from [dbo].[N_NewsLine]

Answer 3

您可以在使用这些值之前进行检查。

Select  TotalSalesPrice,CurrNewsPrice,IIF(TotalSalesPrice = 0, 
                                            0,
                                            CAST(CurrNewsPrice AS decimal(18,2)) / CAST(TotalSalesPrice AS decimal(18,2)) * 100.00)  AS AvgNews
from [dbo].[N_NewsLine]

Answer 4

用例...当...计算之前

Select  TotalSalesPrice,CurrNewsPrice,
CAST( Case CAST(TotalSalesPrice AS decimal(18,2))
when 0 then 0.00
else CAST(CurrNewsPrice AS decimal(18,2)) / CAST(TotalSalesPrice AS decimal(18,2)) * 100.00 end AS decimal(18,2)) AS AvgNews
from [dbo].[N_NewsLine]

Answer 5

选择TotalSalesPrice，CurrNewsPrice，CAST（CurrNewsPrice AS decimal（18,2））/ CAST（NULLIF（TotalSalesPrice，0）AS decimal（18,2））* 100.00 AS AvgNews来自[dbo]。[N_NewsLine]

Answer 6

如果您希望结果为decimal(18, 2)则在除法后执行cast() 。 分割小数时的结果类型的规则是。 。 。 而拜占庭（没有针对拜占庭人的罪行）。

我建议使用NULLIF()来避免被零除，从而导致：

Select TotalSalesPrice, CurrNewsPrice,
       cast(CurrNewsPrice * 100.00 /
            nullif(TotalSalesPrice, 0) as decimal(18, 2)
           ) as AvgNews
from [dbo].[N_NewsLine]