function 작성하는법

설명 : CREATE OR REPLACE FUNCTION 함수명 (인수)
변수
BEGIN
처리
RETURN (RTN_VAL); --반환
END FUN_CHK_CHANGE;

예제)

CREATE OR REPLACE FUNCTION GET_FUNCTION_NAME (p_param1 in varchar2)
return varchar2
is v_return varchar2(10);
begin
IF p_param1 = 'A1' THEN
select A1 into v_return from test where id = 1;
ELSIF p_param1 = 'A2' THEN
select A2 into v_return from test where id = 1;
END IF;

return (v_return);
end;