PHP,类别,SELECT FROM INNERJOIN WHERE

2023年11月30日 221次阅读

嗨我试图让这个特定的代码适用于类别页面.不知道如何安排.

        $cat = $_GET['cat'];
}
$record_count = $db->query("SELECT * FROM posts WHERE category_id='$cat'");
$per_page = 3;
$pages = ceil($record_count->num_rows/$per_page);

echo $cat;

if (isset($_GET['p']) && is_numeric($_GET['p'])){
    $page = $_GET['p'];
}else{
    $page = 1;
}
if($page<=0)
    $start=0;
    else
    $start = $page * $per_page - $per_page;
$prev = $page - 1;
$next = $page + 1;
$query = $db->prepare("SELECT post_id, title, date, image, LEFT(body, 150) AS  body, category FROM posts WHERE posts.category_id=$cat INNER JOIN categories ON categories.category_id=posts.category_id order by post_id desc limit $start, $per_page");
$query->execute();
$query->bind_result($post_id, $title, $date, $image, $body, $category );

这包括pagnation,特别是看这一行.但要隔离所需的category_id似乎比预期的更难(至少对我来说)

$query = $db->prepare("SELECT post_id, title, date, image, LEFT(body, 150) AS  body, category FROM posts WHERE posts.category_id=$cat INNER JOIN categories ON categories.category_id=posts.category_id order by post_id desc limit $start, $per_page");

使用两个mysql表

帖子：post_id标题日期图片正文链接linkname category_id

类别：category category_id

最佳答案 你的查询部分不按顺序排列(具体来说,WHERE去的地方)并且你没有正确地编写预备语句.请注意,您在每个变量的位置放置一个问号,然后使用bind_param按顺序填写问号.第一部分“iii”表示有三个整数.

$query = $db->prepare("SELECT post_id, title, date, image, LEFT(body, 150) AS  body, category 
    FROM posts 
    INNER JOIN categories ON categories.category_id=posts.category_id 
    WHERE posts.category_id=? 
    order by post_id desc 
    limit ?, ?");
$query->bind_param("iii", $cat, $start, $per_page);
$query->execute();
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