how to use sql in case

how to use sql in case

hello it can take on values STATUS = 1 OR STATUS = 0 OR NULL
How can I do ( if or case when )
thank you..
if status = 1
where ICERIK.ACTIVE='1'
else if status 2
where ICERIK.ACTIVE= '0'
else if STATUS NULL
where ICERIK.ACTIVE in ('1','0')
OR
IF STATUS=NULL
where ICERIK.ACTIVE in ('1','0')
ELSE
WHERE ICERIK.ACTIVE=STATUS
PROCEDURE SP_GET_EKSPERTIZ_CONTENT_ARSAID (ARSA_ID IN VARCHAR2,STATUS IN
VARCHAR2, CUR_EKSPERTIZ_ICERIK OUT SYS_REFCURSOR) as
BEGIN
OPEN CUR_EKSPERTIZ_CONTENT FOR
SELECT DISTINCT ICERIK.*,ARSA.*
FROM T_TEM_EKSPERTIZ_ICERIK ICERIK
left outer join T_TEM_ARSA ARSA on ICERIK.GAYRIMENKUL_ID = ARSA.ARSA_ID
WHERE ICERIK.ACTIVE=STATUS
AND ICERIK.GAYRIMENKUL_ID IN
(SELECT *
FROM
TABLE(FN_SPLIT(SP_GET_EKSPERTIZ_CONTENT_ARSAID.ARSA_ID,
',')));
END SP_GET_EKSPERTIZ_CONTENT_ARSAID;