Oracle SQL Multiple Rows Return One Row

//Data table DRIVERHP :-

STAFNO | CONTACTNO
---------------------------------
STAF1 11122
STAF1 44455
STAF2 33344
STAF3 66677
STAF3 88888
STAF3 99988

//works on 10g
//the Select Statement 1 :-

SELECT F.STAFNO, RTRIM(XMLAGG(XMLELEMENT(J, F.CONTACTNO,', ')).EXTRACT('//text()'),', ') AS CONTACTNOS
FROM DRIVERHP F
GROUP BY F.STAFNO

//select statement 2 :-
SELECT F.STAFNO, WM_CONCAT(F.CONTACTNO) AS CONTACTNOS
FROM  DRIVERHP F
GROUP BY F.STAFNO

//SQL output :-

STAFNO | CONTACTNOS
---------------------------------------------------------------------
STAF1 11122, 44455
STAF2 33344
STAF3 66677, 88888, 99988