在SELECT語句中計算錯誤

Question

我有一個SQL我試圖在DatasetAdapter中創建它工作到某個點，但我無法弄清楚最後一點工作。

我有一個表（MainTable）具有以下字段：ID名稱圖像區域平均

我想計算ABS(Area-?) AS Cal1, ABS(Mean-?) AS Cal2 , Cal1+Cal2 As Cal3

SELECT 
ID, Image, Name, Area, Mean, ABS(Area - ?) AS cal1, ABS(Mean - ?) AS cal2, Cal1+Cal2 AS cal3 
FROM MainTable 

我於是想CAL3的最大值

SELECT  MAX(cal3) AS maxofcal3 
FROM   
    (SELECT  ID, Image, Name, Area, Mean, ABS(Area - ?) AS cal1, ABS(Mean - ?) AS cal2, derivedtbl_1.cal1 + derivedtbl_1.cal2 AS cal3 
FROM   MainTable) 
derivedtbl_1 

它迄今爲止工作給我cal3的最大值。

問題： 我想進行另一個計算（Cal3/maxofcal3）。我無法弄清楚。我想下面的代碼，但想出了一個錯誤：

SELECT  MAX(Cal3) AS maxofCal3, Cal3/MaxofCal3 AS Norm 
FROM   (SELECT  ID, Image, Name, Area, Mean, ABS(Area - ?) AS cal1, ABS(Mean - ?) AS cal2, derivedtbl_1.cal1 + derivedtbl_1.cal2 AS cal3 
                derivedtbl_1.Cal1 + derivedtbl_1.Cal2 AS Cal3 
          FROM   MainTable) derivedtbl_1 
GROUP BY Cal3/MaxofCal3. 

Answer 1

集團通過CAL4只，而不是由CAL4/MaxofCal4

檢查下面的例子中得到的想法如何使你的代碼工作：

CREATE TABLE #SampleTable (ID int, Image nvarchar(10), Name nvarchar(10), Area int, Mean int) 


SELECT MAX(Cal3) AS maxofCal3, Cal4/MAX(Cal3) AS Norm 
FROM (
SELECT ID, Image, Name, Area, Mean, ABS(Area - 1) AS cal1, ABS(Mean - 1) AS cal2, ABS(Area - 1) + ABS(Area - 1) AS cal3, ABS(Area - 1) + ABS(Area - 1) AS Cal4 FROM #SampleTable 
) derivedtbl_1 
GROUP BY Cal4 


DROP TABLE #SampleTable