Small Mod question

[Ipuck]

I'm making a small and simple mod for my site. Th users enters some data, the data is stored in a table and then every time the users access the page, the mod run a query and get the users data.

Problem:

I can only get the script to run the query and echo the results if the user access the page like this: http://xxx.com/forum/mypage.php?username=xxxxxx

Question:

Is there any way to run the query as soon as the user enter the page?

just by typing the page : http://xxx.com/forum/mypage.php

I don't have PHP experience and any help will be appreciated.