No. To overload a function, you must change the "signature" of the function, which is the defined by the position and datatype of the inputs. The return value is not part of the signature, so it can't be used for overloading.
"Oracle Database 11g PL/SQL Programming," by Michael McLaughlin, page 318
answered Jan 17 '10 at 03:36 AM
The answer is NO. Since we cannot overload the functions based on its return types.
answered Jan 12 '10 at 12:34 PM