使用數學計算百分比

Question

OK，想象我有200行一列，每行是一個值是由4,8,2或0。有沒有一種方法來劃分的時候2,0出現COUNT反對4和8的COUNT時間發生？像這樣：

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

謝謝！ :)

編輯：

上了下面的語句0除錯誤，雖然這樣做COUNT（*），其中Completion_Event_Type_Key IN（2,0）或（8,4）返回300萬行

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

你可以這樣說：

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 

零謹防師，雖然。如果不存在具有4,8行的行，則可能需要特殊處理。

鑑於你的問題查詢，您的SQL應該是這個樣子：

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