"Philippe Amelant" <pamelant@companeo.com> writes:
> In the first case you have a month with 31 days and in the second you
> have a month with 30 days
The interval comparisons have no way to know that, so they arbitrarily
assume that '1 month' is equivalent to '30 days'. This isn't going to
be changed. If you don't like it, don't use age(). A plain old
timestamp subtraction will probably provide behavior that's closer to
what you want.
regards, tom lane