如何在php中获取标题和指向上一篇和下一篇文章的链接

Question

我是 PHP 新手，通过开发一个小的 CRUD 博客来学习。我现在面临的挑战是如何在用户打开文章后获取标题和指向上一篇和下一篇博文的链接。这是为了确保轻松导航到下一篇和上一篇文章，而无需点击后退按钮来选择下一篇文章。

下面的图片解释了我的写作。 enter image description here

我已尝试查询数据库并使用 > than id 或 less than id 链接到下一篇和上一篇文章，但均无效。

 <?php
    $previous = "SELECT * FROM posts WHERE `posts`.`id` < $id";
    $next = "SELECT * FROM posts WHERE `posts`.`id` > $id";                      
    echo "<li><a href='{{url('post.php/' . $previous)}}'> Previous</a></li>";
    echo "<li><a href='{{url('post.php/' . $next)}}'> Next</a></li>";
?>    

我实际上想要上一个和下一个链接指向下一篇和上一篇文章的标题。

Answer 1

#current blog post

$blog_id = 5;
$b_query=$conn->prepare("SELECT * FROM blogs WHERE blog_id=:id AND blog_status=:status");
$b_query->execute(array(
    'id' => $blog_id,
    'status' => 1
));
$b_query_get=$b_query->fetch(PDO::FETCH_ASSOC);

/* We check the existence of such data from the database. */
$single_post_control=$b_query->rowCount();
if($single_post_control == 0   ){
    echo "error";
    exit;
}

/* next post - previous post*/
$b_pre_nex=$conn->prepare("SELECT * FROM blogs WHERE   blog_id = (SELECT MIN(blog_id)  FROM blogs WHERE blog_id > :pre_nex_id AND blog_status=:pre_nex_status )  OR blog_id = (SELECT MAX(blog_id) FROM blogs WHERE blog_id < :pre_nex_id AND blog_status=:pre_nex_status) ");
$b_pre_nex->execute(array(
    'pre_nex_id' => $blog_id_get,
    'pre_nex_status' => 1
));

$control=$b_pre_nex->rowCount();
if($control == 0 || $control  > 3  ){
    echo "error";
    exit;
}

/* Here, we are splitting our previous and next posts separately.*/
$prev_post = $b_pre_nex->fetch(PDO::FETCH_ASSOC);
$next_post = NULL;
while ( $rows = $b_pre_nex->fetch(PDO::FETCH_ASSOC) ) {
    $next_post = $rows;
}
if(!isset($next_post)) {
    $next_post = null;
}


echo '<a href="#" style="float:left">'.$prev_post['blog_name'].'</a>';

echo '<a href="#" style="float:right">'.$next_post['blog_name'].'</a>';

也许它可以派上用场。

Answer 2

/**
 * Rows per page
 */
$limit = 1;

// Find out how many items are in the table
$total = $db->get_total_count('cat_id', 'category', array('show_home_page' => 1, 'type_id' => 5, 'status' => 1));


// How many pages will there be
$pages = ceil($total / $limit);

// What page are we currently on?
$page = min($pages, filter_input(INPUT_GET, 'page', FILTER_VALIDATE_INT, array(
    'options' => array(
        'default'   => 1,
        'min_range' => 1,
    ),
)));

// Calculate the offset for the query
$offset = ($page - 1)  * $limit;

// Some information to display to the user
$start = $offset + 1;
$end = min(($offset + $limit), $total);

// The "back" link
$prevlink = ($page > 1) ? '<a href="#prev" class="program_nav" data-id="'.($page - 1).'" title="Back"><i class="fa fa-chevron-left"></i></a>' : '<a href="#prev" class="disabled" title="Back"><i class="fa fa-chevron-left"></i></a>';

// The "forward" link
$nextlink = ($page < $pages) ? '<a href="#next" class="program_nav" data-id="'.($page + 1).'" title="Next"><i class="fa fa-chevron-right"></i></a>' : '<a href="#next" class="disabled" title="Next"><i class="fa fa-chevron-right"></i></a>';


$total_query = 'SELECT COUNT(cat_id) FROM category WHERE show_home_page = 1 AND type_id = 5 AND status = 1';

$query = 'SELECT c.name, c.url FROM category as c WHERE c.show_home_page = 1 AND c.type_id = 5 AND c.status = 1 ORDER BY c.order ASC';

$programs = $db->get_table_custom($total_query, $query, true, $limit, $page);