使用数学计算百分比

Question

OK，想象我有200行一列，每行是一个值是由4,8,2或0。有没有一种方法来划分的时候2,0出现COUNT反对4和8的COUNT时间发生？像这样：

(COUNT(2, 0)/COUNT(4, 8)) * 100 

谢谢！ :)

编辑：

上了下面的语句0除错误，虽然这样做COUNT（*），其中Completion_Event_Type_Key IN（2,0）或（8,4）返回300万行

SELECT DISTINCT 

    SD.Last_Secondary_School_Name AS 'School', ((SELECT COUNT(*) where CC.Completion_Event_Type_Key IN (2,0))/(SELECT COUNT(*) where CC.Completion_Event_Type_Key IN (4, 8)))*100 

FROM [AUTDataWarehouse].[dbo].[Fact_Admission] AS FA 

INNER JOIN [AUTDataWarehouse].[dbo].[Dim_Student_Demographics] AS SD ON SD.Student_Demographics_Key = FA.Student_Demographics_Key 

INNER JOIN [AUTDataWarehouse].[dbo].[Fact_SDR_Course_Completion] AS CC ON FA.Student_Demographics_Key = CC.Student_Demographics_Key 

GROUP BY 

SD.Last_Secondary_School_Name, CC.Completion_Event_Type_Key 

ORDER BY SD.Last_Secondary_School_Name 

Answer 1

你可以这样说：

select 
    sum(case when value in (2,0) then 1 else 0 end)/
    sum(case when value in (4,8) then 1 else 0 end) * 100 
from table 

零谨防师，虽然。如果不存在具有4,8行的行，则可能需要特殊处理。

鉴于你的问题查询，您的SQL应该是这个样子：

SELECT  
    SD.Last_Secondary_School_Name AS 'School', 
    sum(case when CC.Completion_Event_Type_Key IN (2,0) then 1 else 0 end)/
    sum(case when CC.Completion_Event_Type_Key IN (4,8) then 1 else 0 end) * 100  

FROM [AUTDataWarehouse].[dbo].[Fact_Admission] AS FA 

INNER JOIN [AUTDataWarehouse].[dbo].[Dim_Student_Demographics] AS SD ON SD.Student_Demographics_Key = FA.Student_Demographics_Key  
INNER JOIN [AUTDataWarehouse].[dbo].[Fact_SDR_Course_Completion] AS CC ON FA.Student_Demographics_Key = CC.Student_Demographics_Key 

GROUP BY SD.Last_Secondary_School_Name, CC.Completion_Event_Type_Key 

ORDER BY SD.Last_Secondary_School_Name