php - 比较 Laravel 5 中两个不同表的时间戳

Question

我试图通过仅显示上次检查后更新的结果(由 $last_check 定义)来获取联合结果

$last_check = CheckNotifications::where('notif_check_user_id', '=', $user_id)->pluck('updated_at');

$get_projects = DB::table('requests')
    ->join('notifications', 'notifications.notif_project_id', '=', 'requests.id')
    ->select(DB::raw('requests.updated_at, requests.request_name, "" as fullname, "P" as flag'))
    ->where('notif_user_id', '=', $user_id)
    ->whereRaw('requests.updated_at > requests.created_at');

$comments = DB::table('project_comments')
    ->leftJoin('users', 'comment_user_id', '=', 'users.id')
    ->leftJoin('requests', 'comment_project_id', '=', 'requests.id')
    ->select(DB::raw('project_comments.updated_at, requests.request_name, users.fullname, "C" as flag'));

$get_notifications = $get_projects->union($comments)
    ->whereRaw('updated_at > $last_check')
    ->orderBy('updated_at', 'desc')
    ->get();

在我添加最后一个 whereRaw 语句之前，联合工作得很好。添加该语句后，我收到 SQL 语法/访问错误 (#42000)。我认为这与为进行比较而提取 Updated_at 有关。有任何想法吗？提前致谢!

编辑:这是错误代码

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 '15:09:06) union (select project_comments.updated_at, requests.id as request_id, ' at line 1 (SQL: (select requests.updated_at, requests.id as request_id, requests.request_name, "" as fullname, "P" as flag from `requests` inner join `notifications` on `notifications`.`notif_project_id` = `requests`.`id` where `notif_user_id` = 1 and requests.updated_at > requests.created_at and requests.updated_at > 2015-07-29 15:09:06) union (select project_comments.updated_at, requests.id as request_id, requests.request_name, users.fullname, "C" as flag from `project_comments` left join `users` on `comment_user_id` = `users`.`id` left join `requests` on `comment_project_id` = `requests`.`id`) order by `updated_at` desc) 

Answer 1

应该有2个updated_at列，请附上您的错误，同时再次提及类似的内容，我无法确定原因。

解决办法很简单，将表名写在列名之前 改变

   ->whereRaw('updated_at > $last_check')

进入

  ->whereRaw('requests.updated_at > $last_check')

并将 orederby() 更改为 whereRaw() 之后 你之前就写了几行正确的代码:D 我希望这能解决您的问题