[Sql] Oracle - Select시 자동 num 증가

SELECT
    DECODE(MAX(group_cd),NULL,'0001',LPAD(MAX(group_cd)+1,4,'0')) group_cd
FROM
    table

 SELECT

    DECODE(MAX('0001'),NULL,'0001',LPAD(MAX('001')+1,5,'0')) group_cd

FROM

    dual;