Just try this

Flicked from jmodic's prev. post

SELECT
TRUNC(sysdate,'YYYY')+ROWNUM -1,
TO_CHAR(TRUNC(sysdate,'YYYY')+ROWNUM -1,'MONTH'),
TO_CHAR(TRUNC(sysdate,'YYYY')+ROWNUM -1,'DD'),
ROWNUM
FROM all_objects
WHERE TRUNC(sysdate,'YYYY')+ROWNUM -1 < ADD_MONTHS(TRUNC(sysdate,'YYYY'),12);

Cheers!