Basic Oracle Concepts and Programming Question:

A sub function is a function defined and used inside another procedure or function. You need to define a sub function in the declaration part of the enclosing procedure or function. Sub function definition starts with the FUNCTION key word. Here is a sample script showing you how to define and use a sub function:

SQL> CREATE OR REPLACE PROCEDURE SUM_TEST AS
2 FUNCTION MY_SUM(X NUMBER, Y NUMBER)
3 RETURN NUMBER AS
4 BEGIN
5 RETURN X + Y;
6 END;
7 BEGIN
8 DBMS_OUTPUT.PUT_LINE('3 + 5 = ' ||
9 TO_CHAR(MY_SUM(3,5)));
10 DBMS_OUTPUT.PUT_LINE('5 + 3 = ' ||
11 TO_CHAR(MY_SUM(5,3)));
12 END;
13 /

SQL> EXECUTE SUM_TEST;
3 + 5 = 8
5 + 3 = 8