使用偏移误差限制 [重复]

Question

我正在使用 Ajax 加载项目，并且我使用了偏移量

JS：

var offset = 0;

$(".load-more").click(function() {
    offset+=5;
    $(this).addClass("spin");
    $.ajax({
      url: '/api/fetchitems.php?offset='+offset+'&sort='+sort,
      success: function(data){
        $(".load-more").before(data);
      }
    });
});

PHP/SQL：

$offset = intval($_GET["offset"]);

$stmt = $db->prepare(
 "SELECT s.id,s.date,s.title,s.views,s.image,s.hidpi,s.width,s.description,u.display_name,u.avatar, s.hotness
  FROM showcase AS s
  INNER JOIN users AS u ON s.user_id = u.id
  UNION ALL
  SELECT q.id,q.date,q.title,q.views,0,0,0,q.text,u.display_name,u.avatar, q.hotness
  FROM questions AS q
  INNER JOIN users AS u ON q.user_id = u.id
  ORDER BY hotness DESC
  LIMIT :skip, 5
  ");
$stmt->bindParam(":skip",$offset);
$stmt->execute();
$items = $stmt->fetchAll();
$stmt = null;

我在执行时收到此错误：

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''5', 5' at line 9' in **** Stack trace: #0 **** PDOStatement->execute() #1 {main} thrown in

当我在 phpMyAdmin 中运行 SQL 时，它运行良好。

Answer 1

你的:skip 被引号包裹起来，好像它是一个字符串（因为默认设置是PDO::PARAM_STR），这是错误的，你现在得到：

LIMIT '5',5;

根据documentation，可以将类型改为int：

$stmt->bindParam(":skip",$offset, PDO::PARAM_INT);

这在您的 PhpMyAdmin 中有效的原因是您没有添加单引号。

Answer 2

$stmt = $db->prepare(
 "SELECT s.id,s.date,s.title,s.views,s.image,s.hidpi,s.width,s.description,u.display_name,u.avatar, s.hotness
  FROM showcase AS s
  INNER JOIN users AS u ON s.user_id = u.id
  UNION ALL
  SELECT q.id,q.date,q.title,q.views,0,0,0,q.text,u.display_name,u.avatar, q.hotness
  FROM questions AS q
  INNER JOIN users AS u ON q.user_id = u.id
  ORDER BY hotness DESC
  LIMIT :skip, 5 
  ");

$stmt->bindParam(':skip', $offset, PDO::PARAM_INT);

你想这样做