function in plsql

1CREATE FUNCTION function_name … RETURN BOOLEAN IS
2	Definitions;
3BEGIN
4	Statement;
5	RETURN "Hello World!";
6END;

1CREATE OR REPLACE FUNCTION my_schema.my_function(param1 IN number) RETURN output1 IS
2    cnumber NUMBER;
3BEGIN
4    cnumber := 2;
5    RETURN (cnumber * param1);
6EXCEPTION
7    WHEN OTHERS THEN
8        raise_application_error(-20001, 'An error was encountered - '
9            || sqlcode || ' -ERROR- ' || sqlerrm);
10END;