hi. I am new to htaccess and need help to create something like this:

if i go to mydomain.com/category1 i must get opened mydomain.com/categories.php?cat=category1

if i go to mydomain.com/category1/02 i must get opened mydomain.com/categories.php?cat=category1?page=result2

Can you help me please?

why don't use permalinks of wordpress? it is human and easy!

I think we could handle this in htaccess thusly:

Redirect /category1 http://mydomain.com/categories.php?cat=category1
Redirect /category1/02 http://mydomain.com/categories.php?cat=category1?page=result2

I inserted this code into my root .htaccess. When I visited mysite/category1 I was sent to a 404 that told me that /categories.php?cat=category1 could not be found on my server. Instead of the 404, of course, your categories.php would handle the request.

Therefore, the Redirect works.