I found a simpliar query that works for me.
But it uses 3 queries. I was wondering if there was a
way to just use one.
qrySumBought:-
SELECT [BookID], [BookType], Sum([QtyBought]) AS SumOfQtyBought
FROM BookBought
GROUP BY [BookID], [BookType];
qrySumSold:-
SELECT [BookID], [BookType], Sum([QtySold]) AS SumOfQtySold
FROM BookSold
GROUP BY [BookID], [BookType];
qryStockOnHand:-
SELECT [Book].[BookID], [Book].[BookType],
nz([SumOfQtyBought])-nz([SumOfQtySold]) AS [Stock On Hand]
FROM (Book LEFT JOIN qrySumBought ON ([Book].[BookID]=[qrySumBought].[BookID]) AND ([Book].[BookType]=[qrySumBought].[BookType])) LEFT JOIN qrySumSold ON ([Book].[BookID]=[qrySumSold].[BookID]) AND ([Book].[BookType]=[qrySumSold].[BookType]);