MS Access具有条件的多个联接

Question

I'm generating an Inventory Query and the below code (mostly) works but it includes Invoices that have been voided, resulting in negative inventory.

Void Yes/No field = tblInvoices.Void

tblInvoiceDetails.InvoiceNum = tblInvoices.ID

I can't figure out how to ensure this does not include invoices that were voided. Thank you in advance for your help!

SELECT tblInventory.ID, Nz(sumTotalPaid,0)-Nz(sumCreditAmount,0) AS Quantity
FROM (tblInventory 
LEFT JOIN (
    SELECT ProductID, Sum(Quantity) AS sumTotalPaid
    FROM tblOrderDetails
    GROUP BY tblOrderDetails.ProductID
)  AS sum1 
   ON tblInventory.ID = sum1.ProductID) 
LEFT JOIN (
    SELECT ProductID, Sum(Quantity) AS sumCreditAmount
    FROM tblInvoiceDetails
    GROUP BY tblInvoiceDetails.ProductID
)  AS sum2 
    ON tblInventory.ID = sum2.ProductID;

Answer 1

Try it this way:

SELECT tblInventory.ID, Nz(sumTotalPaid,0)-Nz(sumCreditAmount,0) AS Quantity
FROM (tblInventory  
JOIN (
    SELECT ProductID, Sum(Quantity) AS sumTotalPaid
    FROM tblOrderDetails
    GROUP BY tblOrderDetails.ProductID
)  AS sum1 
   ON tblInventory.ID = sum1.ProductID) 
JOIN (
    SELECT ProductID, Sum(Quantity) AS sumCreditAmount
    FROM tblInvoiceDetails
    WHERE tblInvoiceDetails.InvoiceNum IN 
        (SELECT tblInvoices.ID
        FROM tblInvoices
        WHERE tblInvoices.Void='Yes')
    GROUP BY tblInvoiceDetails.ProductID
)  AS sum2 
    ON tblInventory.ID = sum2.ProductID

1.- First you use just JOIN instead of LEFT JOIN , so you just get the rows that have values in both tables.

2.- You get only the Products that have the tblInvoices.Void='Yes'