Help needed - Subdomain forwarding

[rik72]

I am going to use hostname.com as an example in this,

 

I have created a DNS record for all subdomains so they all turn back to the default directory of the domain.

 

I am trying to create a php script which will check the URL, if there is no subdomain, or the subdomain is equal to "www." to set the page header to home.php

 

if it's equivalent to anything else i want it to set the header to another page home2.php, and set "subdomain".hostname.com as a variable.. change the "subdomain" to "id" in mysql.. (this part i can manage..)

 

For example..

 

hello.hostname.com would header as hostname.com/home2.php?sub=1 (if hello = 1 in the mysql database)

www.hostname.com would header as hostname.com/home.php

hostname.com would header as hostname.com/home.php