用sql隐藏PHP分页系统中的一些页面 - hide some pages from php pagination system with sql

正如标题所说，我想对分页系统隐藏一些页面。因为它选择的表是巨大的，所以它创建了成千上万的数字。

所以我希望它是这样的第一页1 2 3 4…最后一页

如果我点击页面，它应该显示这个第一页1 2 3 4 5 6 7 8…最后一页

如果我点击第8页，它应该显示这个第一页…4 5 6 7 8 9 10 11…最后一页

这是我的php分页脚本

<!DOCTYPE html>
<html>
  <head>
    <title>PHP Pagination</title>
  </head>
<body>
    <table align="center" border="2" cellpadding="3">
        <tr>
            <th>Name</th>
            <th>quality</th>
            <th>RequiredLevel</th>
        </tr>
        <?php
            $con = mysqli_connect('127.0.0.1', 'root', 'ascent', 'world');
            $per_page=500;
            if (isset($_GET["page"])) {
                $page = $_GET["page"];
            }else{
                $page=1;
            }
            $start_from = ($page-1) * $per_page;
            $stmt = $con->prepare("SELECT name, Quality, RequiredLevel  FROM item_template LIMIT $start_from, $per_page");
            $stmt->execute();
            $stmt->bind_result($name, $quality, $reqlvl);
            $stmt->store_result();
            while($stmt->fetch()) {
                if($stmt->num_rows > 0) {
                    echo "<tr align='center'>";
                    echo "<td>$name</td>";
                    echo "<td>$quality</td>";
                    echo "<td>$reqlvl</td>";
                    echo "</tr>";
                }
            }
        ?>
    </table>
    <div>
        <?php
            $stmt = $con->prepare("SELECT * FROM item_template");
            $stmt->execute();

            $stmt->store_result();
            if($stmt->num_rows > 0) {
                $total_records = $stmt->num_rows;
                $total_pages = ceil($total_records / $per_page);
                echo "<center><a href='index.php?page=1'>First Page</a>";
                for ($i=1; $i<=$total_pages; $i++) {
                    if($page < 4)
                    echo "<a href='index.php?page=$i'>$i</a> ";
                }
                echo "<a href='index.php?page=$total_pages'>Last Page</a></center> ";       
            }
        ?>
    </div>
</body>
</html>

对于分页问题的解决方案如下:

使用超全局$_GET获取当前页码，

// current page
$current_page = isset($_GET['page']) ? $_GET['page'] : 1;

查找页面的超集范围，如1-10或1-20等。例如，如果$total_pages = 30，那么这个超集范围将是1-30。这一步的代码如下:
```
// superset range of pages
$superset_range = range(1, $total_pages);
```

查找要显示的页面子集范围，如1-7或3-9等。例如，如果$total_pages = 30，那么这个子集范围将是1-7，或3-9，或6-12等，它可以是1到30之间的任何连续7页。此外，在必要时调整这个范围。这一步的代码如下:

// subset range of pages to display
$subset_range = range($current_page - 3, $current_page + 3);
// adjust the range(if required)
foreach($subset_range as $p){
    if($p < 1){
        array_shift($subset_range);
        if(in_array($subset_range[count($subset_range) - 1] + 1, $superset_range)){
            $subset_range[] = $subset_range[count($subset_range) - 1] + 1;
        }
    }elseif($p > $total_pages){
        array_pop($subset_range);
        if(in_array($subset_range[0] - 1, $superset_range)){
            array_unshift($subset_range, $subset_range[0] - 1);
        }
    }
}

最后，显示相应的分页链接和点。这一步的代码如下:

// display intermediate pagination links
if($subset_range[0] > $superset_range[0]){
    echo " ...&nbsp;";
}
foreach($subset_range as $p){
    echo "<a href='index.php?page=$p'>$p</a>";
}
if($subset_range[count($subset_range) - 1] < $superset_range[count($superset_range) - 1]){
    echo "&nbsp;... ";
}

那么，这里是完整的代码:

// your code
$stmt = $con->prepare("SELECT * FROM item_template");
$stmt->execute();
$stmt->store_result();
if($stmt->num_rows > 0) {
    $total_records = $stmt->num_rows;
    $total_pages = ceil($total_records / $per_page);
    if($total_records > $per_page){
        echo "<center><a href='index.php?page=1'>First Page</a> ";
        // current page
        $current_page = isset($_GET['page']) ? $_GET['page'] : 1;
        // Superset range of pages
        $superset_range = range(1, $total_pages);
        // subset range of pages to display
        $subset_range = range($current_page - 3, $current_page + 3);
        // adjust the range(if required)
        foreach($subset_range as $p){
            if($p < 1){
                array_shift($subset_range);
                if(in_array($subset_range[count($subset_range) - 1] + 1, $superset_range)){
                    $subset_range[] = $subset_range[count($subset_range) - 1] + 1;
                }
            }elseif($p > $total_pages){
                array_pop($subset_range);
                if(in_array($subset_range[0] - 1, $superset_range)){
                    array_unshift($subset_range, $subset_range[0] - 1);
                }
            }
        }
        // display intermediate pagination links
        if($subset_range[0] > $superset_range[0]){
            echo " ...&nbsp;";
        }
        foreach($subset_range as $p){
            echo "<a href='index.php?page=$p'>$p</a>";
        }
        if($subset_range[count($subset_range) - 1] < $superset_range[count($superset_range) - 1]){
            echo "&nbsp;... ";
        }
        echo " <a href='index.php?page=$total_pages'>Last Page</a></center> ";  
    }    
}