function getQueryString(Array $newQuery, $keepOld) {
	static $currentQueryArray;
	
	// check to see if the current 
	if(!is_array($currentQueryArray)) {
		$currentQueryArray = array();
		parse_str($_SERVER['QUERY_STRING'], $currentQueryArray);
	}
	
	if($keepOld) $newQueryArray = array_merge($currentQueryArray, $newQuery);
	else $newQueryArray = $newQuery;
	
	return http_build_query($newQueryArray);
}

More of a setQueryString

Create Query String

php, query, update

PHP