I am trying to add a partial month to a date in oracle. i tried like this

```
SELECT months_between('1-DEC-2014',SYSDATE) FROM dual

```

i get -2.79041218637993

then i tried to add (subtract) this result to sysdate.

```
SELECT add_months(trunc(SYSDATE), -2.79041218637993) FROM dual

```

i thought i should have gotten '1-DEC-2014' but it only added the 2 full months and left the .79041218637993 out so it returned 12/25/2014.

any ideas how i can get it to add the partial month as well so that it will return 12/01/2014?