MS Access Query to output all values and treat unavailable values as zero

Question

I've created a query MS Access 2010 that is intended to take all fuel types (all values) for each date. I have the query relationship below: ) and have the following 6 values for fuel type: Diesel #2, MSFO, ULSD, Biodiesel, Used Oil, Heat Recovery.

I'm trying to output the fuel delivery for each fuel type for each date regardless if there's any fuel delivered that date and . What I'm getting as my output is below .

I have tried to change the relationships such that all values on tbl_FuelType would output. This gave me the output on the figure above. I've tried entering a criteria to look for the specific fuel type (e.g. "ULSD") but if there's no data for that day, it will output with Null values, which I don't want. See criteria below I've tried some program flow functions such as IIF and Switch but still getting null values. Is there an easy way to do this without having to go into the table and filling out values as zero's for all the different fuel types on the tbl_FuelDelivery? The SQL view is as follows:

SELECT tbl_FuelDelivery.DateLog, Sum(Nz([tbl_FuelDelivery].[F_FO_gal_Gross],0)) AS Fuel_Delivery_Gross, Sum(Nz([tbl_FuelDelivery].[F_FO_gal_Net],0)) AS Fuel_Delivery_Net, tbl_FuelType.FuelType
FROM tbl_FuelType LEFT JOIN tbl_FuelDelivery ON tbl_FuelType.ID = tbl_FuelDelivery.FuelType
GROUP BY tbl_FuelDelivery.DateLog, tbl_FuelType.FuelType
ORDER BY tbl_FuelDelivery.DateLog;
​

Answer 1

您需要添加到查询中的是包含所有日期的表格。您可以拥有一个单独的表格，其中输入所有日期，例如日历表格，或者从tbl_FuelDelivery得到它，如下所示：

SELECT DISTINCT tbl_FuelDelivery.DateLog 
FROM tbl_FuelDelivery;

现在，您需要使用tbl_FuelType CROSS JOIN此表。 Access本身不支持交叉连接，因此您必须使用解决方法：只需将交叉连接作为逗号分隔表添加到FROM子句：

SELECT a.DateLog, tbl_FuelType.FuelType, tbl_FuelType.ID
FROM (SELECT DISTINCT tbl_FuelDelivery.DateLog FROM tbl_FuelDelivery) a, 
tbl_FuelType;

上面的查询将为您提供所有日期的所有燃料类型。您可以将其另存为新查询（我们称之为allDatesFuels）。现在，您需要做的就是将其与您的查询相结合：

SELECT 
allDatesFuels.DateLog, 
Sum(Nz([tbl_FuelDelivery].[F_FO_gal_Gross],0)) AS Fuel_Delivery_Gross, 
Sum(Nz([tbl_FuelDelivery].[F_FO_gal_Net],0)) AS Fuel_Delivery_Net, 
allDatesFuels.FuelType
FROM allDatesFuels LEFT JOIN tbl_FuelDelivery ON allDatesFuels.ID = tbl_FuelDelivery.FuelType And allDatesFuels.DateLog = tbl_FuelDelivery.DateLog
GROUP BY allDatesFuels.DateLog, allDatesFuels.FuelType
ORDER BY allDatesFuels.DateLog;
​