<?php

// url = "www.domain.com/a/b/c?sort=price";

var_dump($_GET['query']);       // will return string(5) "a/b/c"
var_dump($_SERVER['REQUEST_URI']);  // will return string(17) "/a/b/c?sort=price"

// htaccess will give you the value for query
// now we parse the REQUEST_URI, to get the value for "sort" (if it exists)

$regex = '/\?sort=([^&]+)(?:&|$)/';
$sort = preg_match($regex, $_SERVER['REQUEST_URI'], $regs) ? $regs[1] : ""; // $sort = 'price'

var_dump($sort);

?>