I have the following code snippet. It works when the value in the variable TotalDue is 0 or greater. However if TotalDue has a negative value, it returns 0 instead of the correct value. For instance, if TotalDue is 100 and Sum_Memo is 50, it will return 50. However, if TotalDue is -100, then instead of returning -150, it returns 0. TotalDue and SumMemo are string variables. How can I fix it so it will show the correct value. incidentally, the colon in front of the variable just indicates that it an external variable, it does not have any bearing on the final result.
alDue),0) - NVL(To_Number(:Sum_Memo),0