php mysql按查询排序错误

我有posts表的以下属性- id、标题、类别id、内容、发布日期。 对于类别表： 身份证和姓名

我在$query中得到一个错误。=“orderbyposts.id”

---

我觉得你的查询结构不正确。

WHERE

子句前面应该有一个空格，

orderby

也应该有一个空格

$posts = array();
$query = ("SELECT posts.id AS post_id, categories.id AS category_id, title, contents, date_posted, categories.name AS name FROM posts INNER JOIN categories ON categories.id = posts.cat_id");

if (isset($id)) {
  $id=(int)$id;
  $query .= " WHERE posts.id={$id}"; // note whitespace before WHERE
}

$query .= " ORDER BY posts.id DESC"; // note whitespace before ORDER BY here
$query = mysql_query($query);

---

假设您使用的是php，请尝试使用mysqli。Mysql本身就遭到了本的抨击。这可能是导致错误的原因您知道串联的作用吗？可能是空白？如果（！isset（$id））

会发生什么？
$posts = array();
$query = ("SELECT posts.id AS post_id, categories.id AS category_id, title, contents, date_posted, categories.name AS name FROM posts INNER JOIN categories ON categories.id = posts.cat_id");

if (isset($id)) {
  $id=(int)$id;
  $query .= " WHERE posts.id={$id}"; // note whitespace before WHERE
}

$query .= " ORDER BY posts.id DESC"; // note whitespace before ORDER BY here
$query = mysql_query($query);