SELECT Invoice Total, Payment Total, Credit Total, Invoice Total - Payment Total - Credit Total AS Balance Due FROM Invoices; The BalanceDue in the output of this statement is called a derived or calculated column because it is not defined in the Invoices table but in this statement. In other words, there is no BalanceDue data can be found in the Invoices table. Assume that, there are some invoices in the Invoices table, their Payment Total or CreditTotal or both have no data value for some reasons. Discuss, for these invoices, what will be the reasonable value of BalanceDue at the output of this statement and explain why SELECT Invoice Total, Payment Total, Credit Total, Invoice Total - Payment Total - Credit Total AS Balance Due FROM Invoices; The BalanceDue in the output of this statement is called a derived or calculated column because it is not defined in the Invoices table but in this statement. In other words, there is no BalanceDue data can be found in the Invoices table. Assume that, there are some invoices in the Invoices table, their Payment Total or CreditTotal or both have no data value for some reasons. Discuss, for these invoices, what will be the reasonable value of BalanceDue at the output of this statement and explain why