如何在PHP中获取两个日期之间的差异? [重复]

Possible Duplicate:
How to calculate the date difference between 2 dates using php

date1=2010-11-10 09:49:54;
date2=2010-11-10 09:49:54;

How do I get difference between these two dates in PHP?

$difference = strtotime($date1) - strtotime($date2);

The difference will be in seconds.