php怎么实现分页和删除功能

<?php
  $page_num = isset($_GET['page']) ? $_GET['page'] : 1;
  $rows_per_page = 10;

  // connect to MySQL database
  $conn = mysqli_connect('localhost', 'username', 'password', 'database');
  if (!$conn) {
    die('Failed to connect to database: ' . mysqli_connect_error());
  }

  // get total number of rows
  $result = mysqli_query($conn, 'SELECT COUNT(*) as count FROM products');
  $row = mysqli_fetch_assoc($result);
  $total_rows = $row['count'];

  // calculate the number of pages
  $total_pages = ceil($total_rows / $rows_per_page);

  // calculate the starting row index
  $start = ($page_num - 1) * $rows_per_page;

  // retrieve the data
  $sql = "SELECT * FROM products LIMIT $start, $rows_per_page";
  $result = mysqli_query($conn, $sql);

  // display the data
  while ($row = mysqli_fetch_assoc($result)) {
    echo $row['product_name'] . ' - ' . $row['product_price'] . '<br>';
  }

  // display the pagination links
  for ($i = 1; $i <= $total_pages; $i++) {
    if ($i == $page_num) {
      echo '<b>' . $i . '</b> ';
    } else {
      echo '<a href="?page=' . $i . '">' . $i . '</a> ';
    }
  }

  // close the connection
  mysqli_close($conn);
?>

<?php
  // connect to MySQL database
  $conn = mysqli_connect('localhost', 'username', 'password', 'database');
  if (!$conn) {
    die('Failed to connect to database: ' . mysqli_connect_error());
  }

  // get the product id to delete
  $product_id = $_GET['product_id'];

  // delete the product
  $sql = "DELETE FROM products WHERE id = $product_id";
  mysqli_query($conn, $sql);

  // close the connection
  mysqli_close($conn);

  // redirect to the product list page
  header('Location: products.php');
?>