PHP Date Difference Function?

Hi

Why is not there any date difference function in the PHP library? Where they have plenty of other small functions why dont they have a basic date difference function as this is a very useful and important function?

I know there are such functions over the internet if you google but you dont found this function in their official php.net site.

Do you know why?

I have no clue what you just said. But I'm assuming it's asking about why php has all the little small functions in between. So I'll answer that, the functions are used for different things. So say I want to insert something into a mysql database, I may wanna use mktime().