在MS Access中，必須比較兩個不同表中的值，並找出值之間的差異？

Question

我有兩個不同的表，表1和表2

Table 1 
----------- 
Resource 
Start Date 
End date 
Total Hours 

Table 2 
------------ 
Resource 
Reource type 
Total Hours 

這裏我有根據所述資源的總小時的每個表的匹配，然後 必須找到不匹配的數據，並找到差值與那些不匹配數據的值。

Answer 1

SELECT [Table 1].[Resource], 
     ([Table 1].[Total Hours] - [Table 2].[Total Hours]) As Difference 
FROM [Table 1] 
INNER JOIN [Table 2] 
    ON [Table 1].[Resource] = [Table 2].[Resource] 
WHERE [Table 1].[Total Hours] <> [Table 2].[Total Hours] 

如果我理解正確的話，這會給你時間總計和它所屬的資源的差異。括號是必要的，因爲可怕的列和表名稱。

Answer 2

也許[資源]不是表1中的唯一鍵。 所以我們需要一些分組的條款：

SELECT Resource,SUM([Total Hours]) As SumHours1 
INTO #SumHours1 
FROM [Table 1] 
GROUP BY [Resource]; 

SELECT Resource,SUM([Total Hours]) As SumHours2 
INTO #SumHours2 
FROM [Table 2] 
GROUP BY [Resource]; 

SELECT Resource,SumHours1,SumHours2 
FROM #SumHours1 LEFT OUTER JOIN #SumHours2 
ON #SumHours1.Resource=#SumHours2.Resource