I suppose to follow these instructions:

Make a list of 20 patients

Create a total of all account balances, so that the total amount of receivables can be known

For each account, calculate the number of days each balance has been outstanding

Classify the accounts into four categories three late(30,60, and 90 days overdue and one current ( under 30 days) Total the amount of outstanding receivables for each of these categories

Sort the database using the number of days the account balance is outstanding as the primary sort key and the outstanding balance as the secondary sort key.

Save the newly sorted database.

My question is shouldn't all calculations take place in a query and not in tables?