PHP - Site Navigation Help

while ($row = mysqli_fetch_array($results, MYSQLI_ASSOC)){


echo '<div class="media margin-none">
<a class="pull-left bg-inverse innerAll text-center" href="#"><img src="'.$foto.'" share_alt="" width="100" height="100"></a>
<div class="media-body innerAll">
<h4 class="media-heading innerT">
<a href="' . $row['title'] .'-da' . $row['id_ad'] . '" class="text-inverse">'. $remuneracion .' &nbsp; ' . substr(ucfirst(strtolower($row['title'])), 0, 53) . '</a> <small class="pull-right label label-default"><i class="fa fa-fw fa-calendar-o"></i> ' . $row['date_created'] . '</small></h4>
<p>' . substr(ucfirst(strtolower($row['description'])), 0, 80) . ' ...</p>';

echo '</div>
</div>
<div class="col-separator-h"></div>';
}

echo pagination($statement,$per_page,$page, $url_filtros, $filtros);
?>

Hello! Can someone please explain to me why I do not read navigation from mysql database data?

Database

Code:
 

<style type="text/css">
    .navbar .dropdown-toggle, .navbar .dropdown-menu a {
        cursor: pointer;
    }

    .navbar .dropdown-item.active, .navbar .dropdown-item:active {
        color: inherit;
        text-decoration: none;
        background-color: inherit;
    }

    .navbar .dropdown-item:focus, .navbar .dropdown-item:hover {
        color: #16181b;
        text-decoration: none;
        background-color: #f8f9fa;
    }

    @media (min-width: 767px) {
        .navbar .dropdown-toggle:not(.nav-link)::after {
            display: inline-block;
            width: 0;
            height: 0;
            margin-left: .5em;
            vertical-align: 0;
            border-bottom: .3em solid transparent;
            border-top: .3em solid transparent;
            border-left: .3em solid;
        }
    }
</style>
<script type="text/javascript">
    $(document).ready(function () {
        $('.navbar .dropdown-item').on('click', function (e) {
            var $el = $(this).children('.dropdown-toggle');
            var $parent = $el.offsetParent(".dropdown-menu");
            $(this).parent("li").toggleClass('open');

            if (!$parent.parent().hasClass('navbar-nav')) {
                if ($parent.hasClass('show')) {
                    $parent.removeClass('show');
                    $el.next().removeClass('show');
                    $el.next().css({"top": -999, "left": -999});
                } else {
                    $parent.parent().find('.show').removeClass('show');
                    $parent.addClass('show');
                    $el.next().addClass('show');
                    $el.next().css({"top": $el[0].offsetTop, "left": $parent.outerWidth() - 4});
                }
                e.preventDefault();
                e.stopPropagation();
            }
        });

        $('.navbar .dropdown').on('hidden.bs.dropdown', function () {
            $(this).find('li.dropdown').removeClass('show open');
            $(this).find('ul.dropdown-menu').removeClass('show open');
        });

    });
</script>

<?php 
$servername = "localhost";
$username = "root";
$password = "";

$db = new PDO("mysql:host=$servername;dbname=dbname", $username, $password);

function menu_builder1($db, $parent_id) {
    $sql = $db->prepare("SELECT * FROM menu WHERE status = 1 ORDER BY position ASC");
    if($sql->execute()) {
        while ($row = $sql->fetch(PDO::FETCH_ASSOC)) {
            $array[$row['menu_sub_id']][] = $row;
        }
        main_menu1($array);
    }
}
function main_menu1($array, $parent_id = false) {
    if(!empty($array[$parent_id])) {
        foreach ($array[$parent_id] as $item) {
            if ($item['dropdown'] == false) {
                echo '<li class="nav-item active"><a class="nav-link" href="' . $item['href'] . '">' . $item['name'] . '</a></li>';
            }
            elseif ($item['dropdown'] == true) {
                echo '<li class="nav-item dropdown"><a class="nav-link dropdown-toggle" id="dropdown2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">' . $item['name'] . '</a>';
                sub_menu1($array, $item['menu_id']);
                echo '</li>';
            }
        }
    }
}
function sub_menu1($array = array(), $parent_id = false) {
    if(!empty($array[$parent_id])) {
        echo '<ul class="dropdown-menu" aria-labelledby="dropdown2">';
        foreach ($array[$parent_id] as $item) {
            if ($item['dropdown'] == false) {
                echo '<li class="dropdown-item"><a href="' . $item['href'] . '">' . $item['name'] . '</a></li>';
            }
            elseif ($item['dropdown'] == true) {
                echo '<li class="dropdown-item dropdown"><a class="dropdown-toggle" id="dropdown2-1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">' . $item['name'] . '</a>';
                sub_sub_menu1($array, $item['menu_id']);
                echo '</li>';
            }
        }
        echo "</ul>";
    }
}

function sub_sub_menu1($array = array(), $parent_id = false) {
    if(!empty($array[$parent_id])) {
        echo '<ul class="dropdown-menu" aria-labelledby="dropdown2-1">';
        foreach ($array[$parent_id] as $item) {
            if ($item['dropdown'] == false) {
                echo '<li class="dropdown-item"><a href="' . $item['href'] . '">' . $item['name'] . '</a></li>';
            }
        }
        echo "</ul>";
    }
}
?>
<div class="navbar navbar-expand-md navbar-dark bg-dark mb-4" role="navigation">
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarCollapse">
        <ul class="navbar-nav mr-auto">
            <?=menu_builder1($db, 0)?>
        </ul>
    </div>
</div>

Result: