在LEFT JOIN上打破了分页

时间：2017-07-12 10:45:28

标签： php html mysql pagination

我改变了我的分页，因为它没有第一个/上一个和下一个/最后一个导航功能到一个版本。

我改变它的原因是因为页面底部会有30多个编号的链接，而且它看起来很丑陋而且看起来不专业。

除了网站上的两个部分外，分页适用于我的所有页面。奇怪的是，这两个页面的 LEFT JOIN 就像下面的示例一样，但不同之处在于它们依赖于为每个页面选择 categoryID 来显示数据

Working Pagination

以下是PHP＆amp;的新代码示例。 MySQL和代码的HTML。

使用PHP＆amp; MySQL的 

//PAGINATION
try {
    $totalPages  = $DB->query(" SELECT COUNT(id) as rows 
                                FROM art_categories LEFT JOIN articles
                                ON articles.categoryID=art_categories.categoryID
                                WHERE articles.categoryID=art_categories.categoryID
                                AND art_categories.categoryID NOT IN
                                    (SELECT categoryID
                                     FROM art_categories
                                     WHERE categoryID=8)
                                AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                AND state = 1")
              ->fetch(PDO::FETCH_OBJ);

    $posts  = $totalPages->rows;
    $pages  = ceil($posts / $perpage);

    # default
    $get_pages = isset($_GET['page']) ? $_GET['page'] : 1;

    $data = array(

        'options' => array(
            'default'   => 1,
            'min_range' => 1,
            'max_range' => $pages
            )
    );

    $number = trim($get_pages);
    $number = filter_var($number, FILTER_VALIDATE_INT, $data);
    $range  = $perpage * ($number - 1);

    $prev = $number - 1;
    $next = $number + 1;

    $stmt = $DB->prepare("SELECT * FROM articles WHERE publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH ) LIMIT :limit, :perpage");
    $stmt->bindParam(':perpage', $perpage, PDO::PARAM_INT);
    $stmt->bindParam(':limit', $range, PDO::PARAM_INT);
    $stmt->execute();

    $result = $stmt->fetchAll();

} catch(PDOException $e) {
    $error = $e->getMessage();
}

使用HTML 

<ul class="pagination">
    <?php

            if($result && count($result) > 0)
            { ?>
            <li <?php if($_GET['page'] >= 2) { echo('class=""'); } else { echo('class="disabled"'); } ?> >
                <a href="<?php if($_GET['page']==1 || $_GET['page']==0) { echo('#');} else { echo ('index.php?page=1'); } ?>">FIRST</a>
            </li>
            <li <?php if(!empty($_GET['page']) && $_GET['page']==1 || $_GET['page']==0) { echo('class="disabled"');} ?>>
                <a <?php if($_GET['page']==1 || $_GET['page']==0) { echo('class="disabled"');} ?> href="<?php if($_GET['page']==1 || $_GET['page']==0) { echo('#');} else { echo ('index.php?page='. $prev); } ?>">&laquo; PREVIOUS</a>
            </li>
            <li class="active">
                <a href="index.php?page=<?php echo $get_pages; ?>"><?php echo $get_pages; ?></a>
            </li>
            <li <?php if($_GET['page']==$pages) { echo('class="disabled"');} ?>>
                <a href="<?php if($_GET['page']==$pages) { echo('#');} else { echo ('index.php?page='. $next); } ?>">NEXT &raquo;</a>
            </li>
            <li <?php if($_GET['page']==$pages) { echo('class="disabled"');} ?>>
                <a href="<?php if($_GET['page']==$pages) { echo('#');} else { echo ('index.php?page='. $pages); } ?>">LAST</a>
            </li>

    <?php } ?>
</ul>

到目前为止，一切都很好。一旦我尝试在类别和广告商的其他页面上执行左LEFT JOIN，我的分页功能就不起作用。

我收到以下错误代码：

注意：未定义的变量：导致第15行的C：\ wamp64 \ www \ Bushvelder \ categories.php

这是代码中的第15行：

if($result && count($result) > 0)

我将在“类别”页面中包含以下代码，因为我相信，一旦我对其进行了排序，我也可以修复广告商页面分页。

破解PHP＆amp; MySQL的 

$catID = $_GET['categoryID'];

//PAGINATION
try {
    $totalPages  = $DB->query(" SELECT COUNT(id) as rows 
                                FROM art_categories LEFT JOIN articles
                                ON articles.categoryID=art_categories.categoryID
                                WHERE articles.categoryID={$catID}
                                AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                AND state = Publish")
              ->fetch(PDO::FETCH_OBJ);

    $posts  = $totalPages->rows;
    $pages  = ceil($posts / $perpage);

    # default
    $get_pages = isset($_GET['page']) ? $_GET['page'] : 1;

    $data = array(

        'options' => array(
            'default'   => 1,
            'min_range' => 1,
            'max_range' => $pages
            )
    );

    $number = trim($get_pages);
    $number = filter_var($number, FILTER_VALIDATE_INT, $data);
    $range  = $perpage * ($number - 1);

    $prev = $number - 1;
    $next = $number + 1;

    $stmt = $DB->prepare("  SELECT *
                            FROM art_categories LEFT JOIN articles
                            ON articles.categoryID=art_categories.categoryID
                            WHERE articles.categoryID={$catID}
                            AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                            AND state = Publish
                            ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
    $stmt->bindParam(':perpage', $perpage, PDO::PARAM_INT);
    $stmt->bindParam(':limit', $range, PDO::PARAM_INT);
    $stmt->execute();

    $result = $stmt->fetchAll();

} catch(PDOException $e) {
    $error = $e->getMessage();
}

HTML CODE 

<ul class="pagination">
    <?php

        if($result && count($result) > 0)
        { ?>
            <li <?php if($_GET['page'] >= 2) { echo('class=""'); } else { echo('class="disabled"'); } ?> >
                <a href="<?php if($_GET['page']==1 || $_GET['page']==0) { echo('#');} else { echo ('categories.php?categoryID='. $article['categoryID'] . '&amp;page=1'); } ?>">FIRST</a>
            </li>
            <li <?php if(!empty($_GET['page']) && $_GET['page']==1 || $_GET['page']==0) { echo('class="disabled"');} ?>>
                <a <?php if($_GET['page']==1 || $_GET['page']==0) { echo('class="disabled"');} ?> href="<?php if($_GET['page']==1 || $_GET['page']==0) { echo('#');} else { echo ('categories.php?'. $article['categoryID'] . '&amp;page='. $prev); } ?>">&laquo; PREVIOUS</a>
            </li>
            <li class="active">
                <a href="categories.php?categoryID=<?php echo $article['categoryID']; ?>&amp;page=<?php echo $get_pages; ?>"><?php echo $get_pages; ?></a>
            </li>
            <li <?php if($_GET['page']==$pages) { echo('class="disabled"');} ?>>
                <a href="<?php if($_GET['page']==$pages) { echo('#');} else { echo ('categories.php?'. $article['categoryID'] . '&amp;page='. $next); } ?>">NEXT &raquo;</a>
            </li>
            <li <?php if($_GET['page']==$pages) { echo('class="disabled"');} ?>>
                <a href="<?php if($_GET['page']==$pages) { echo('#');} else { echo ('categories.php?'. $article['categoryID'] . '&amp;page='. $pages); } ?>">LAST</a>
            </li>

    <?php } ?>
</ul>

我强烈怀疑我搞砸了我的MySQL，但我不知道从哪里开始。非常感谢任何帮助。

如果我在回答之前弄明白，我会发布我的发现。

修改

好吧所以我用 LIMIT：limit，：perpage 修正了错误，但我仍然在第15行得到错误，如上所述。

1 个答案:

答案 0 :(得分：0)

所以这就是我为解决问题所做的工作。

<强>第一 对于与我的分页问题相关的所有变量，我使用 var_dump（$ variable）进行了一些变量转储。

<?php echo var_dump($result); ?>
<?php echo var_dump($totalPages); ?>
<?php echo var_dump($pages); ?>
<?php echo var_dump($get_pages); ?>
<?php echo var_dump($posts); ?>
<?php echo var_dump($stmt); ?>
<?php echo var_dump($catID); ?>
<?php echo var_dump($article['categoryID']); ?>
<?php echo var_dump($_GET['page']); ?>

这给了我宝贵的见解，了解哪些变量在其中具有值，哪些变量为空。

然后我转到原始代码：

$stmt = $DB->prepare("  SELECT *
                        FROM art_categories LEFT JOIN articles
                        ON articles.categoryID=art_categories.categoryID
                        WHERE articles.categoryID={$catID}
                        AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                        AND state = Publish
                        ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
$stmt->bindParam(':perpage', $perpage, PDO::PARAM_INT);
$stmt->bindParam(':limit', $range, PDO::PARAM_INT);
$stmt->execute();

然后我通过PHP设置各种 SWITCH CASES ，看看当我点击我的菜单时 categoryID 是否确实在改变。而这确实在起作用。

switch ($catID) {
        case 1:
            $stmt = $DB->prepare("  SELECT art_categories.*, articles.*
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=1
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 2:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=2
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 3:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=3
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 4:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=4
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 5:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=5
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 6:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=6
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 7:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=7
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
        case 8:
            $stmt = $DB->prepare("  SELECT *
                                    FROM art_categories LEFT JOIN articles
                                    ON articles.categoryID=art_categories.categoryID
                                    WHERE articles.categoryID=8
                                    AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                                    AND state = Publish
                                    ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
            break;
    }

然后我查看了 VAR_DUMP 数据，并且$ result变量仍然发布为null。所以我决定查看我的疑问。我经历了多次查询代码迭代，尝试了 JOIN 的不同方法，看看它如何影响我的 VAR_DUMP 数据。

然后我告诉我，我最初在我的MySQL查询中使用的 LEFT JOIN 没有问题，因为它与使用 LEFT JOIN 的其他页面一起运行

我开始测试我的查询，直到最后成功！

$catID = $_GET['categoryID'];

//PAGINATION
try {

    $totalPages  = $DB->query(" SELECT COUNT(id) as rows 
                                FROM art_categories LEFT JOIN articles
                                ON articles.categoryID=art_categories.categoryID
                                WHERE articles.categoryID = {$catID}
                                AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )")
              ->fetch(PDO::FETCH_OBJ);

    $posts  = $totalPages->rows;
    $pages  = ceil($posts / $perpage);

    # default
    $get_pages = isset($_GET['page']) ? $_GET['page'] : 1;

    $data = array(

        'options' => array(
            'default'   => 1,
            'min_range' => 1,
            'max_range' => $pages
            )
    );

    $number = trim($get_pages);
    $number = filter_var($number, FILTER_VALIDATE_INT, $data);
    $range  = $perpage * ($number - 1);

    $prev = $number - 1;
    $next = $number + 1;

    $stmt = $DB->prepare("  SELECT *
                            FROM art_categories LEFT JOIN articles
                            ON articles.categoryID=art_categories.categoryID
                            WHERE articles.categoryID = {$catID}
                            AND articles.publishDate >= DATE_ADD( NOW( ) , INTERVAL -2 MONTH )
                            ORDER BY articles.publishDate DESC LIMIT :limit, :perpage");
    $stmt->bindParam(':perpage', $perpage, PDO::PARAM_INT);
    $stmt->bindParam(':limit', $range, PDO::PARAM_INT);
    $stmt->execute();

    $result = $stmt->fetchAll();

} catch(PDOException $e) {
    $error = $e->getMessage();
}

因此，经过所有的测试后， AND state = Publish 似乎是打破我的分页的罪魁祸首，导致数小时的挫折，浪费时间和刮伤。我创建的 ENUM 似乎存在问题，以检查内容是否以DRAFT或PUBLISH状态保存。

我从中学到了什么？

  • 保持冷静，不要惊慌
  • 使用 var_dump（）来测试变量
  • 设置不同的 CASE SWITCHES 真的帮助了我
  • 正确排查问题
  • 不要放弃
  • 学到一些新技巧
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