分页在第二页上没有显示正确的结果

Question

我一直试图将这项工作推迟一段时间。我有一个<select标记用于显示页面上的结果数量。显然，查询可以显示所有行，但是当我转到第二页时，它不再起作用。我已经检查了一个关于使用$_REQUEST变量但没有用的帖子。

FORM

<form method="POST" action="test.php" class="navbar-form navbar-left">
            <div class="form-group">
                <select class="form-control" id="adNum" name="showAdsOptions" aria-describedby="categoryHelp"> 
                    <option value="10">Show 10 ads per page</option>
                    <option value="15">Show 15 ads per page</option>
                    <option value="20">Show 20 ads per page</option>
                </select>
                <input type="submit" name="filterAds" class="form-control" value="Go" />
            </div>
</form>

表格

    <table class="table table-bordered">
        <?php

        include 'admin/script/connection.php';
        $limit = 5;
        $counter = 1;
        $me = $_SESSION['user'];

        $selectSQL = "SELECT * FROM user_pending_ads WHERE User_Name='$me'";
        $result = $conn->query($selectSQL);
        $total = $result->num_rows;

        if (isset($_GET['p']) == null) {
            $p = 0;
        } else {
            $p = $_GET['p'];
            if($p == 1) {
                $p = $p-1;
            } else {
                $p = ($p-1) * $limit;
            }
        }

        if ($limit > $total) {
            $nop = 1;
        } else {
            $nop = $total/$limit;
        }
        $nop = ceil($nop);
        $display = "SELECT * FROM user_pending_ads WHERE User_Name='$me' LIMIT $p, $limit";

        // SEARCH QUERY
        if (isset($_GET['searchAds'])) {
            if (isset($_GET['q']) == null) {
                $display = "SELECT * FROM user_pending_ads WHERE User_Name='$me' LIMIT $p, $limit";
            } else {
                $search = $_GET['q'];
                if ($search == "") {
                    $display = "SELECT * FROM user_pending_ads WHERE User_Name='$me' LIMIT $p, $limit";
                } else {
                    $display = "SELECT * FROM user_pending_ads WHERE User_Name='$me' AND Ad_Title LIKE '%$search%' LIMIT $p, $limit";
                }
            }
        }

        // IF SHOW # ADS PER PAGE IS SET AND GO IS CLICKED
        if (isset($_POST['filterAds']) == true) {
            $opt = $_REQUEST['showAdsOptions'];
            $display = "SELECT * FROM user_pending_ads WHERE User_Name='$me' LIMIT $p, $opt";
        }

        $getdisplay = $conn->query($display);
        while ($col = $getdisplay->fetch_assoc()) {
            ...
        }
        ?>
    </table>

分页

<ul class="pagination">
            <?php
            if ($total >= 1) {
                ?>
                <li><a href="?p=1" class="btn btn-info">First</a></li>
                <?php
                for ($i = 1; $i <= $nop; $i++) {
                ?>
                    <li><a href="?p=<?php echo $i ?>" class="btn btn-info"><?php echo $i ?></a></li>
                <?php
                }
            ?>
            <li><a href="?p=<?php echo $nop ?>" class="btn btn-info">Last</a></li>
            <?php
            }
            ?>
</ul>