删除按钮不起作用？

Question

管理员：

<?php
  $per_page=50;
  if (isset($_GET["page"])) 
  {
    $page = $_GET["page"];
  }
  else 
  {
    $page=1;
  }
  $start_from = ($page-1) * $per_page;

  $sql="select * from all_colleges LIMIT $start_from, $per_page";
  $result = mysqli_query($link,$sql);
  while ($row = mysqli_fetch_array($result)) 
  {
  echo "<tr>
          <td>".$row['college_id']."</td>
          <td>".$row['college_name']."</td>
          <td>
            <a class='update' title='Update' href='update.php?college_id=".$row['college_id']."'>
              edit
            </a>

            <a class='delete' title='delete' href='delete.php?college_id=".$row['college_id']."'>
              delete
            </a>
          </td>
        </tr>";
  }
?>

<?php
  $query = "select * from all_colleges";
  $result = mysqli_query($link, $query);
  $total_records = mysqli_num_rows($result);
  $total_pages = ceil($total_records / $per_page);
  echo "<center><a href='admin.php?page=1' style='padding:10px;'>".'First Page'."</a>";
  $skipped = false;
    for ($i = 1; $i <= $total_pages; $i++)  {
        if ($i < 3 || $total_pages- $i < 3 || abs($page - $i) < 3) {
            if ($skipped)
                echo '<span> ... </span>';
            $skipped = false;
            echo "<a href='admin.php?page=" . $i . "' style='padding:5px;'>" . $i . "</a>";
        } else {
            $skipped = true;
        }
    }
  echo "<a href='admin.php?page=$total_pages' style='padding:10px;'>".'Last Page'."</a></center>";
?>

delete.php

<?php 
  include('../../conn.php');
  $college_id=$_GET['college_id'];
  $sql = "delete from all_colleges where college_id='$college_id'";
  $result = mysqli_query($link,$sql);
  if($result)
  {
    header('location:admin.php');
  }
?>

在这段代码中，我在admin.php页面中有一个删除按钮，我在其中使用分页。当我点击删除按钮记录不删除时我不知道为什么？我该如何解决这个问题？请帮忙。

谢谢