select
dt1, dt2,
trunc( months_between(dt2,dt1) ) mths,
dt2 - add_months( dt1, trunc(months_between(dt2,dt1)) ) days
from
(
select date '2012-01-01' dt1, date '2012-03-25' dt2 from dual union all
select date '2012-01-01' dt1, date '2013-01-01' dt2 from dual union all
select date '2012-01-01' dt1, date '2012-01-01' dt2 from dual union all
select date '2012-02-28' dt1, date '2012-03-01' dt2 from dual union all
select date '2013-02-28' dt1, date '2013-03-01' dt2 from dual union all
select date '2013-02-28' dt1, date '2013-04-01' dt2 from dual union all
select trunc(sysdate-1) dt1, sysdate from dual
) sample_data
Resultados:
| DT1 | DT2 | MTHS | DAYS |
----------------------------------------------------------------------------
| January, 01 2012 00:00:00 | March, 25 2012 00:00:00 | 2 | 24 |
| January, 01 2012 00:00:00 | January, 01 2013 00:00:00 | 12 | 0 |
| January, 01 2012 00:00:00 | January, 01 2012 00:00:00 | 0 | 0 |
| February, 28 2012 00:00:00 | March, 01 2012 00:00:00 | 0 | 2 |
| February, 28 2013 00:00:00 | March, 01 2013 00:00:00 | 0 | 1 |
| February, 28 2013 00:00:00 | April, 01 2013 00:00:00 | 1 | 1 |
| August, 14 2013 00:00:00 | August, 15 2013 05:47:26 | 0 | 1.241273 |
Enlace para probar:SQLFiddle
