If $_server['query_string'] Not Set Than Do Nothing..?

[cyfer65]

how can i make my PHP page check if a value is set for the $_SERVER['QUERY_STRING'] and if a URL is there then do something with it, but if nothing is set after the ? in the URL string then have it do nothing..how can i accomplish this..??

[justsomeguy]

if ($_SERVER['QUERY_STRING'] != ''){  ...}