下面是我的代码。我想删除管理员，如果超过1个管理员存在和警报在这种情况下完美的工作。但是当我想删除管理员，而管理员是唯一的管理员，我希望页面警告说：“只有1管理员存在。无法删除“”。但是，代码不会显示ay警报，只是刷新页面。我在代码中遗漏了什么？

<div style="width: 60%;" class="jumbotron">
          <form action="deleteAdmin.php" method = "post">
            <p class="h5">Are you sure you want to delete your account?</p>
            <input name="deleteMe" class="btn btn-danger" type="submit" value="Delete"
            id = "login">
            <a href="Settings.php" type="button" class="btn btn-outline-secondary">Cancel</a>
          </form>
          <?php
                if(isset($_POST['deleteMe']))
                {
                    $username = $_SESSION['username1'];
                    $query = 'select * from admins';
                    $query_run = mysqli_query($con, $query);

                    if(mysqli_num_rows($query_run)>1)
                    {
                        $query = "delete from admins where email='$username'";
                        $query_run = mysqli_query($con,$query);
                        session_destroy();
                        echo '<script type="text/javascript"> alert("Admin Deleted Successfully!!!");
                              document.location.href="../adminLogin.php";</script>';
                    }
                    else {
                      echo '<script type="text/javascript"> alert("You are the only admin...
                                Cannot remove the sole admin of a database..");
                            document.location.href="Settings.php";</script>';
                    }
                }
          ?></div>