Get top 15 quiz scorers

functions.php

add_shortcode('wplms_quiz_top_scorers',function($atts,$content = null){
    
     extract(shortcode_atts(array(
            'count'   => 5,
        )));

    global $wpdb;

    $results = $wpdb->get_results("select meta_key as user_id,sum(meta_value) as total from $wpdb->postmeta as m left join $wpdb->posts as p on p.ID = m.post_id where p.post_type = 'quiz' and m.meta_key REGEXP '^[0-9]+$' group by user_id order by total DESC limit 0,$count");

    $html='';
    if(!empty($results)){
        $html.='<div class="quiz_top_scores">';
        foreach($results as $result){
            $html.='<div class="quiz_top_scorer">';
            $html.='<div class="student_avatar">'.bp_core_fetch_avatar(array('item_id'=>$result->user_id,'type'=>'thumb')).'</div>';
            $html .='<div class="student_details">
            '.bp_core_get_user_displayname($result->user_id).'
            <span>'.$result->total.'</span>
            </div>';
            

            $html .='</div>';    
        }
        $html .='</div>';
    }

    return $html;
});