@francis I think he's using the word 'timestamp' loosely as the time of day. But yes, as everyone agrees so far, just use the timestamp which has all the date information and then comparison is trivial.
Since we all seem to be having fun wasting time on a Thursday, I did it in Python for demonstration purposes. I set 'a' to now and then 'b' to now a few seconds later and then arbitrarily set 'c' to a time within the period. This is date-sensitive.
Python 2.7.3 (default, Dec 5 2012, 11:30:37)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime
>>> a = datetime.datetime.now()
>>> a
datetime.datetime(2013, 5, 2, 10, 42, 36, 877059)
>>> b = datetime.datetime.now()
>>> b
datetime.datetime(2013, 5, 2, 10, 42, 50, 684714)
>>> c = datetime.datetime(2013, 5, 2, 10, 42, 49, 000000)
>>> c
datetime.datetime(2013, 5, 2, 10, 42, 49)
>>> bool(a <= b < c)
False
>>> bool(a <= c < b)
True
>>>
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