How to declare local variables in PL/SQL stored programs

Question

Where do I declare local variables in a PL/SQL stored program?
I get compiler errors with either of the options below:
FUNCTION GET_PRINCIPAL_BALANCE (CUT_OFF_DATE IN DATE, TITLE_SN IN DATE, TOTAL_BALANCE OUT NUMBER) RETURN NUMBER IS
TOTAL_BALANCE NUMBER;
BEGIN
RETURN TOTAL_BALANCE;
END;
FUNCTION GET_PRINCIPAL_BALANCE (CUT_OFF_DATE IN DATE, TITLE_SN IN DATE, TOTAL_BALANCE OUT NUMBER) RETURN NUMBER IS
BEGIN
TOTAL_BALANCE NUMBER;
RETURN TOTAL_BALANCE;
END;

Answer 1

Your local variable cannot have the same name as the formal out parameter. This is a procedure example, but since functions should not have out parameters anyway ...
session2> CREATE PROCEDURE p (p_id IN NUMBER, p_did OUT NUMBER) AS
  2     p_did NUMBER;
  3  BEGIN
  4     p_did := p_id * 2;
  5  END;
  6  /
Warning: Procedure created with compilation errors.
session2> show error
Errors for PROCEDURE P:
LINE/COL ERROR
0/0      PL/SQL: Compilation unit analysis terminated
1/1      PLS-00410: duplicate fields in RECORD,TABLE or argument list are
         not permittedThe proper way to create a function would be something like:
CREATE FUNCTION f (p_id IN NUMBER) RETURN NUMBER AS
   l_did NUMBER;
BEGIN
  l_did := p_id * 2;
  RETURN l_did;
END;You should really assign a value to the variable before you return it.
John