PHP solution

<?php
    $db = new mysqli('localhost','root','','test');
    $result = $db->query("SELECT students.*,teachers.name FROM students,teachers WHERE students.id='$id' AND students.class = teachers.class");

    if($result->num_rows){
        while ($row = $result->fetch_assoc()) {
            echo 'Name: '.$row['name'];
                       echo 'Class: '.$row['class'];
        }
    }

    mysqli_close($db);
?>