如何用php pdo显示多个一对多和多对多关系的所有记录？

$dsn = 'mysql:host=localhost;dbname=your_database';
$username = 'your_username';
$password = 'your_password';

try {
    $db = new PDO($dsn, $username, $password);
} catch (PDOException $e) {
    echo 'Connection failed: ' . $e->getMessage();
}

$sql = 'SELECT students.name, courses.name
        FROM students
        JOIN student_course ON students.id = student_course.student_id
        JOIN courses ON student_course.course_id = courses.id';

$stmt = $db->prepare($sql);
$stmt->execute();

while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
    echo 'Student: ' . $row['name'] . '<br>';
    echo 'Course: ' . $row['name'] . '<br>';
    echo '<br>';
}