Months_Between inconsistency

Question

Hi all,
I have come across a strange behavior of Months_Between function.
CREATE TABLE getbucket_TEST
AS
SELECT TO_DATE('31-DEC-2009','DD-MON-YYYY') + LEVEL DT
FROM   DUAL
CONNECT BY LEVEL <= 366*6;
SELECT DT - TO_DATE('28-feb-2010','DD-MON-YYYY') DT_DIFF,
       MONTHS_BETWEEN(DT, TO_DATE('28-feb-2010','DD-MON-YYYY')) mon_DIFF,
       DT, TO_DATE('28-feb-2010','DD-MON-YYYY') as_on_dt
FROM   getbucket_TEST;
DT_DIFF     MON_DIFF     DT     AS_ON_DT
28     1     28-MAR-10     28-FEB-10 --check the difference
29     1.03225806451612903225806451612903225806     29-MAR-10     28-FEB-10
30     1.06451612903225806451612903225806451613     30-MAR-10     28-FEB-10
31     1     31-MAR-10     28-FEB-10 --check the difference
..In this case, if I use Months_Between to generate bill on every occurrence of whole number, it would be generated twice in a month, why does it give this kind of output?
*009*

Answer 1

009 wrote:
28     1     28-MAR-10     28-FEB-10 --check the differenceCheck documentation:
MONTHS_BETWEEN returns number of months between dates date1 and date2. If date1 is later than date2, then the result is positive. If date1 is earlier than date2, then the result is negative. <font color=red>If date1 and date2 are either the same days of the month or both last days of months, then the result is always an integer.</font> <font color=blue>Otherwise Oracle Database calculates the fractional portion of the result based on a 31-day month and considers the difference in time components date1 and date2.</font>SY.