how to put a foreach inside a while

    $query4 = $mysqli -> query ("SELECT s.e_mail
                             FROM staff_courses as sc join
                             staff as s
                             on(s.id_staff = sc.id_staff)
                             WHERE sc.id_course = 'C4-1' and sc.roll_staff_course = 'Coordinator'");

while ($valores3 = mysqli_fetch_array($query4)) {
  $aremail = $valores3['e_mail']; 

            foreach ($aremail as $email) {
                echo $email;
        }