以下内容似乎可以确认DateTime类具有比较运算符：
dev:~# php<?phpdate_default_timezone_set('Europe/London');$d1 = new DateTime('2008-08-03 14:52:10');$d2 = new DateTime('2008-01-03 11:11:10');var_dump($d1 == $d2);var_dump($d1 > $d2);var_dump($d1 < $d2);?>bool(false)bool(true)bool(false)dev:~# php -vPHP 5.2.6-1+lenny3 with Suhosin-Patch 0.9.6.2 (cli) (built: Apr 26 2009 20:09:03)Copyright (c) 1997-2008 The PHP GroupZend Engine v2.2.0, Copyright (c) 1998-2008 Zend Technologiesdev:~#
