i have the following code:
"select sum(( receiptDetails.retailprice - receiptDetails.purchaseprice)* receiptDetails.itemcount ) + ((customerReceiptDetails.retailPrice -customerReceiptDetails.purchasePrice)* customerReceiptDetails.itemCount) As Total from receiptDetails,customerReceiptDetails "
am trying to get the gross profit from the two tables: receiptDetails and customerReceiptDetails. the query works well if both tables have values. i tried to use IsNull within the query to sovle the NULL problem but was not successful. any assistance will be highly appreciated.