$csvFile = file('results.csv');
//map csv in simple array
$shortlinks_array = array_map('str_getcsv', $csvFile );
//pass csv array into assoc array
foreach ($shortlinks_array as $shortlink) {
    //print_r($shortlink);
    $shortlinks_assoc_array[] = array ('url'=> $shortlink[0] , 'url_id' =>$shortlink[1] ,'referal' =>$shortlink[2] , 'counter' =>$shortlink[3] );
}
$sortArray = array();
//sort assoc array
foreach($shortlinks_assoc_array as $shortlink_element){
    foreach($shortlink_element as $key=>$value){
        if(!isset($sortArray[$key])){
            $sortArray[$key] = array();
        }
        $sortArray[$key][] = $value;
    }
}
$orderby = "counter";
array_multisort($sortArray[$orderby],SORT_DESC,$shortlinks_assoc_array);

$sorted_by_lnk_clk_array = array_slice($shortlinks_assoc_array, 0, 50, true);

$referals = array();

foreach($shortlinks_assoc_array as $shortlink_element) {
    $referals[] = array('url_id' => $shortlink_element['url_id'], 'url' => $shortlink_element['url'] );
}

$referals_count = array();

foreach ($referals as $referal) {
    $i = 0;
    foreach($shortlinks_assoc_array as $shortlink_element) {
        if ($referal['url_id']==$shortlink_element['referal']) {
            $i++;
            $key_index = $referal['url'];
            $referals_count[$key_index] = $i;
        }
    }
}
$referals_count = array_slice($referals_count, 0, 50, true);
arsort($referals_count);