SQL> SET ECHO ON
SQL> SET SERVEROUTPUT ON
SQL>
SQL> DECLARE
2 temp NUMBER;
3
4 FUNCTION iifn(boolean_expression IN BOOLEAN,
5 true_number IN NUMBER,
6 false_number IN NUMBER)
7 RETURN NUMBER IS
8 BEGIN
9 IF boolean_expression THEN
10 RETURN true_number;
11 ELSIF NOT boolean_expression THEN
12 RETURN false_number;
13 ELSE
14 --nulls propagate, i.e. null input yields null output.
15 RETURN NULL;
16 END IF;
17 END;
18 BEGIN
19 DBMS_OUTPUT.PUT_LINE(iifn(2 > 1,1,0));
20 DBMS_OUTPUT.PUT_LINE(iifn(2 > 3,1,0));
21
22 temp := iifn(null,1,0);
23 IF temp IS NULL THEN
24 DBMS_OUTPUT.PUT_LINE('NULL');
25 ELSE
26 DBMS_OUTPUT.PUT_LINE(temp);
27 END IF;
28 END;
29 /
1
0
NULL
PL/SQL procedure successfully completed.
SQL>