Invalid use of Null

[Guest]

Dale, thanks for taking the time. Whether I get a solution or not, I think it
is damn kind of you. Below is the SQL of the troubling run that gives
"Invalid use of Null":-

SELECT [Invoices Grouped].[Invoice No], [Invoices Grouped].CustomerID,
[Invoices Grouped].ShipName, [Invoices Grouped].ExtendedPrice, [Invoices
Grouped].Freight, [Invoices Grouped].B4VAT, [Invoices Grouped].VAT, [Invoices
Grouped].InvoiceAmount
FROM Customers LEFT JOIN (([Credits Grouped] RIGHT JOIN [Invoices Grouped]
ON [Credits Grouped].CustomerID = [Invoices Grouped].CustomerID) LEFT JOIN
[Payments Grouped] ON [Invoices Grouped].CustomerID = [Payments
Grouped].CustomerID) ON Customers.CustomerID = [Invoices Grouped].CustomerID
GROUP BY [Invoices Grouped].[Invoice No], [Invoices Grouped].CustomerID,
[Invoices Grouped].ShipName, [Invoices Grouped].ExtendedPrice, [Invoices
Grouped].Freight, [Invoices Grouped].B4VAT, [Invoices Grouped].VAT, [Invoices
Grouped].InvoiceAmount
ORDER BY [Invoices Grouped].ShipName;

 

[Guest]

The problem is not obvious. First thing to do is run some ad hoc queries on
the tables involved to see which fields have Null values. Then, try using
the Nz function to eliminate the Nulls in that field.