Почему не работает ajax-запрос?

Файл обработчик

$num = (int)$_GET['num'];  //
$lim = 12;
$sql_1 = "SELECT * FROM `video` ORDER BY `id` DESC LIMIT {:num}, :lim";
$std = $pdo->prepare($sql_1);
$std->bindParam(':num', $num);
$std->bindParam(':lim', $lim);
$std->execute();
$std->fetch(PDO::FETCH_ASSOC);
echo json_encode($std);

ajax-запрос

$(document).ready(function (){
            var num = 21;
            var inProcess = false;
            $(window).scroll(function(){
              if ($(window).scrollTop() + $(window).height() >= $(document).height() - 700 && !inProcess ){
                console.log("1");
              $.ajax({
                url: '../load.php',
                method: 'GET',
                dataType:'json',
                data: "num="+num,
                beforeSend: function(){
                  inProcess = true;
                },
                    success: function(data){
                        $.each(data, function(index, data){
                        $(".videos").append('<div uk-scrollspy="target: > div; cls:uk-animation-fade; delay: 200"><div class="uk-card uk-card-default"><div uk-lightbox><a href="media/' + data.place_of_location + '.mp4'+'" caption="Video"><div class="uk-card-media-top uk-inline uk-inline-clip uk-transition-toggle"><img class="uk-transition-scale-up uk-transition-opaque" src="media/images/' + data.img + '.jpg' + '" alt="' + data.title + '"><div class="uk-position-medium uk-position-cover uk-overlay uk-flex uk-flex-center uk-flex-middle uk-light"><span uk-icon="icon: play-circle; ratio: 3.5"></span></div><div class="uk-light uk-position-bottom-left"><span class="uk-icon uk-icon-image uk-light" style="background-image: url(media/views.png)"></span><span class="uk-text-large">' + data.views + '</span></div></div></a></div><div class="uk-card-body"><p>' + data.title + '</p></div></div></div>');
                        });
                        inProcess = false;
                        num += 12;
                    }
              });
              }
            });
        });

Запрос в бд для вывода на главной странице

$limit = 22;
$sql_2 = "SELECT * FROM video ORDER BY id DESC LIMIT ?";
$mov = $pdo->prepare($sql_2);
$mov->bindValue(1, $limit, PDO::PARAM_INT);
$mov->execute();