php - fatal error : Call to a member function bind_param() on a non-object

Question

$stmt = $db->prepare("SELECT post_id,content,date,category_id,lp_title,lp_image,lp_canonicalUrl,lp_url,lp_desc,lp_iframe,lp_iframe_id,img_src
    FROM post_items INNER JOIN user ON post_items.user_id = user.user_id INNER JOIN photo_upload ON post_items.post_id = photo_upload.post_id
     WHERE post_items.user_id = ? AND post_items.post_id = photo_upload.post_id order by post_items.post_id desc LIMIT ?,?");


$stmt->bind_param('iii', $userid, $itemStart, $itemEnd);

我这里有 3 个表:user、post_items 和 photo_upload。在我实现 photo_upload 之前，一切正常。

我收到一条错误消息

Fatal error: Call to a member function bind_param() on a non-object in

Answer 1

mysqli::prepare 的文档提到它返回:

mysqli_prepare() returns a statement object or FALSE if an error occurred.

尝试以下操作:

$stmt = $db->prepare("SELECT post_id,content,date,category_id,lp_title,lp_image,lp_canonicalUrl,lp_url,lp_desc,lp_iframe,lp_iframe_id,img_src
    FROM post_items INNER JOIN user ON post_items.user_id = user.user_id INNER JOIN photo_upload ON post_items.post_id = photo_upload.post_id
     WHERE post_items.user_id = ? AND post_items.post_id = photo_upload.post_id order by post_items.post_id desc LIMIT ?,?");

if ($stmt !== false) {
    $stmt->bind_param('iii', $userid, $itemStart, $itemEnd);
} else {
    print_r( $db->error );
}