menu-dinamico

<!DOCTYPE html>
<html lang="pt-BR">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Menu</title>

    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
</head>
<body>
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <a class="navbar-brand" href="#">Navbar</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>

        <div class="collapse navbar-collapse" id="navbarSupportedContent">
            <ul class="navbar-nav mr-auto">
                <li class="nav-item active">
                    <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                </li>

                <?php
                    $host = 'localhost';
                    $user = 'root';
                    $pass = '';
                    $dbname = 'frame_grupo';
                    $link = mysqli_connect($host,$user,$pass,$dbname);
                    mysqli_set_charset($link,'utf8');

                    $sql = "SELECT * FROM menu";
                    $query = mysqli_query($link, $sql);

                    $menu = null;
                    $sub = null;
                    while($row = mysqli_fetch_array($query)){
                        if(strpos($row['nivelmenu'],'.')){
                            $sub[] = [
                                'nivel' => $row['nivelmenu'],
                                'descricao' => $row['descricao']
                            ];
                        }else{
                            $menu[] = [
                                'nivel' => $row['nivelmenu'],
                                'descricao' => $row['descricao']
                            ];
                        }
                    }

                foreach($menu as $m){ ?>

                <li class="nav-item dropdown">
                    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        <?php echo $m['descricao']; ?>
                    </a>

                    <div class="dropdown-menu" aria-labelledby="navbarDropdown">

                        <?php foreach($sub as $s){

                                if(substr($s['nivel'],0,1) == $m['nivel']){?>

                                    <a class="dropdown-item" href="#"><?php echo $s['descricao'];?></a>

                                <?php }
                        }?>
                    </div>
                </li>
                <?php } ?>
            </ul>
        </div>
    </nav>

    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>