I have a table for Account Transaction. For each transaction a user must select a transaction category. These are stored in a second table which has a categoryID, description and a text box with only two values {'Income', 'Expense'}.
Now in the report, I am grouping by Income/Expense. However, I want to be able to calculate the sub-totals of incomes and expenses and then show what the difference is. I am able to calculate the subtotals, but have no idea how to calculate the difference. Ideas?