> I'm not positive if MySQL, PostgreSQL, Oracle, or similar would perform the same date and time manipulation correctly. However, I know from personal experience that MySQL handles date/times more consistently than PHP.

Postgres boasts some very pedantically excellent timestamp and timezone support. If there is a bug, it will be rectified in all possible haste once reported.

For example, from http://www.postgresql.org/docs/9.2/static/functions-datetime...:

    The first century starts at 0001-01-01 00:00:00 AD, although they
    did not know it at the time. This definition applies to all
    Gregorian calendar countries. There is no century number 0, you go
    from -1 century to 1 century. If you disagree with this, please
    write your complaint to: Pope, Cathedral Saint-Peter of Roma,
    Vatican.

    PostgreSQL releases before 8.0 did not follow the conventional
    numbering of centuries, but just returned the year field divided
    by 100.