在Microsoft Access

Question

逗人使用MySQL查询，

不用说了，我已经失去我的脑海里，使这工作完全正常在MySQL工作到Microsoft Access查询。我有一些例外。

这是一个比较查询，该比较查询确实可以比较当前月份和前一个月的耗电量，并按建筑物进行分组。

正如我所说的，它在MySQL中完全正常，但在MS Access中不起作用。

原始查询：

SELECT 
tblElectricReadings.Building, 
SUM(CASE WHEN tblElectricReadings.ReadingDate >= DATE_SUB(NOW(), INTERVAL 1 YEAR) THEN (tblElectricReadings.EndMeter - tblElectricReadings.StartMeter) ELSE NULL END) AS 'Cons1', 
SUM(CASE WHEN tblElectricReadings.ReadingDate BETWEEN DATE_SUB(NOW(), INTERVAL 2 YEAR) AND DATE_SUB(NOW(), INTERVAL 1 YEAR) THEN (tblElectricReadings.EndMeter - tblElectricReadings.StartMeter) ELSE NULL END) AS 'Cons2', 
CONCAT(MONTHNAME(tblElectricReadings.ReadingDate)) AS MonthRecorded 
FROM tblElectricReadings 
WHERE tblElectricReadings.ReadingDate >= DATE_SUB(NOW(), INTERVAL 2 YEAR) 
GROUP BY tblElectricReadings.Building, 
CONCAT(MONTHNAME(tblElectricReadings.ReadingDate)) 
ORDER BY tblElectricReadings.ReadingDate, tblElectricReadings.Building 

我认识的MS Access SQL是有点不同的，所以我潜伏在互联网之后尝试了一些变化。 这是接近我能得到，但它仍然是行不通的：

SELECT 
tblElectricReadings.[Building], 
SUM(IIF(tblElectricReadings.[Reading Date] >= DATEADD("y",-1,NOW()), (tblElectricReadings.[End Meter] - tblElectricReadings.[Start Meter]),0)) AS 'Cons1', 
SUM(IIF(tblElectricReadings.[Reading Date] BETWEEN DATEADD("y",-2,NOW()) AND DATEADD("y",-1,NOW()), (tblElectricReadings.[End Meter] - tblElectricReadings.[Start Meter]),0)) AS 'Cons2', 
MONTHNAME(tblElectricReadings.[Reading Date]) AS MonthRecorded 
FROM tblElectricReadings 
WHERE tblElectricReadings.[Reading Date] >= DATEADD("y",-2,NOW()) 
GROUP BY tblElectricReadings.[Building], MONTHNAME(tblElectricReadings.[Reading Date]) 
ORDER BY tblElectricReadings.[Reading Date], tblElectricReadings.[Building] 

通过上述，我现在得到以下错误：“您的查询不包括指定表达式“tblElectricReadings [。阅读日期]'作为聚合函数的一部分

有没有人有任何线索我做错了什么？当然任何帮助将不胜感激:)道歉，如果我问一些容易，但我仍然在学习很多这里:(

感谢您可以提供任何最终的帮助。

编辑3：我管理！这对我有用 - 感谢所有提供的帮助，我很感激。

SELECT 
tblElectricReadings.[Building], 
MONTHNAME(MONTH(tblElectricReadings.[Reading Date])) AS MonthRecorded, 
SUM(IIF(tblElectricReadings.[Reading Date] >= DATEADD("yyyy",-1,NOW()), (tblElectricReadings.[End Meter] - tblElectricReadings.[Start Meter]),0)) AS [Current Year Consumption], 
SUM(IIF(tblElectricReadings.[Reading Date] BETWEEN DATEADD("yyyy",-2,NOW()) AND DATEADD("yyyy",-1,NOW()), (tblElectricReadings.[End Meter] - tblElectricReadings.[Start Meter]),0)) AS [Previous Year Consumption] 
FROM tblElectricReadings 
WHERE tblElectricReadings.[Reading Date] >= DATEADD("yyyy",-2,NOW()) 
GROUP BY tblElectricReadings.[Building], MONTH(tblElectricReadings.[Reading Date]) 
ORDER BY MONTH(tblElectricReadings.[Reading Date]), tblElectricReadings.[Building]; 

Answer 1

不知道它是唯一的问题，但

SUM(IIF(tblElectricReadings.ReadingDate >= DATEADD("y",-1,NOW()), (tblElectricReadings.EndMeter - tblElectricReadings.StartMeter),"") 

显然是错误的：你不能SUM Strings，即使是空的。尝试改为：

SUM(IIF(tblElectricReadings.ReadingDate >= DATEADD("y",-1,NOW()), (tblElectricReadings.EndMeter - tblElectricReadings.StartMeter),0) 

并对其他事件也做同样的事情。

编辑：

我也认为你的ORDER BY子句是没有意义的，因为它试图订购的东西，不存在这样的输出数据集。它应该是：

ORDER BY MONTHNAME(tblElectricReadings.ReadingDate), tblElectricReadings.Building