Question

我正在使用SQL Server 2014，查询中使用以下语法来计算除法结果。

USE MyDatabase

SELECT 
    ...
    CAST(cte1.[F&B] AS FLOAT) * CAST (cte1.[RN] / cte1.[Total RN] AS FLOAT) AS [F&B_Split],
    CAST(cte1.[F&B] AS FLOAT) * CAST (cte1.[RN] / cte1.[Total RN] AS FLOAT) / CAST(cte1.[GN] AS FLOAT) AS [F&B_Split_PerGN]
    ...
FROM 
    table1

RN中的列GN和table1是整数，列F&B是数字类型。

这是我的结果的一部分：

RN  TOTALRN    GN    F&B    F&B_Split      F&B_Split_PerGN
-------------------------------------------------------------
 9    9        18    1200     1200         66.6666666666667
 9    10       18    3900        0          0

当RN和TotalRN的值相同时（上面的行1），但是对于F＆B_Split和F＆B_Split_PerGN的值（上面的行2），计算似乎可以正常工作。

我在这里做什么错了？

Answer 1

您关心划分的类型。我将删除演员表以浮动。但这是您的选择。

对我来说，最简单的解决方案是在除法之前乘以1.0：

CAST(cte1.[F&B] AS FLOAT) * CAST (cte1.[RN] * 1.0 / cte1.[Total RN] AS FLOAT) AS [F&B_Split],
CAST(cte1.[F&B] AS FLOAT) * CAST (cte1.[RN] * 1.0 / cte1.[Total RN] AS FLOAT) / CAST(cte1.[GN] AS FLOAT) AS [F&B_Split_PerGN]

或者：

cte1.[F&B] * cte1.[RN] * 1.0 / cte1.[Total RN] AS [F&B_Split],
cte1.[F&B]  * cte1.[RN] * 1.0 / cte1.[Total RN]  AS [F&B_Split_PerGN]

如果要为表达式指定特定类型，请转换整个表达式：

convert(float, cte1.[F&B] * cte1.[RN] * 1.0 / cte1.[Total RN]) AS [F&B_Split],
convert(float, cte1.[F&B]  * cte1.[RN] * 1.0 / cte1.[Total RN]) AS [F&B_Split_PerGN]

由于这种划分，为什么在特定的行中得到零？

1 个答案: