In a report I am using the underlying query to calculate extended row totals for 2 different values, Value A and Value B. Each are calculated in the query by CostA*Qty or Cost B*Qty and these work just fine. They also relate in the query to a group, like Group 1 or Group 2.
Then in the report detail area, Group 1 the sum of the CostA*Qty and sum of CostB*Qty work also (text boxes) - BUT I then sum the A total sum and the B total sum into a sub-grand total (text box, again in the detail area) - which works fine unless there is no data in one of the A or B sums.
Example: Sum A = $1,000, Sum B = $200, Sub Grand Total = $1,200 but if
Sum A = $1,000 and Sum B = blank, Sub Grand Total = blank too.