Laravel 5:数据库关系查询

Question

用户->有很多问题->有很多答案

我想为每个问题显示一个最新答案的用户问题信息。

$questions = Question::select('id','user_id',
            'title','video','status','created_at')
            ->where('user_id','=',$user->id)
            ->where('status','>=','2')
            ->with([
                'user' => function($query){
                    $query->select('id','name','picture');
                },
                'answers' => function($query){
                    $query->select('id','question_id','user_id','answer','created_at',DB::raw('count(*) as answer_count'))
                    ->orderBy('created_at','desc')->first();

                },
            ])->get();

在这里，我没有得到每个问题的答案。我得到了用户提交的所有问题的答案

你能帮帮我吗？如何将放在解答的问题id上

预期产出：

User [id, name, and so on ] -> 
question [
    ['id', 'title' ..]->Answer['id','question_id',etc ],
    ['id', 'title' ..]->Answer['id','question_id',etc ]
]

​

​

Answer 1

$questions = Question::select('id','user_id','title','video','status','created_at')->with([
            'user' => function($query){
                $query->select('id','name','picture');
            }
        ])->where('status','>=','2')->get();

        foreach($questions as $question)
        {
            $question_data[] = [
                'id' => $question->id,
                'title' => $question->title,
                'video' => $question->video,
                'user_id' => $question->user_id,
                'status' => $question->status,
                'created_at' => $question->created_at->toDateTimeString(),
                'thumbnail' => $question->thumbnail,
                'user' => [
                    'id' => $question->user->id,
                    'name' => $question->user->name,
                    'picture' => $question->user->picture
                ],
                'answers' => 
                $question->answers()->select('video','question_id','user_id','created_at','thumbnail')
                ->with([
                    'user' => function($query){
                        $query->select('id','name','picture');
                    }
                ])->orderBy('created_at','desc')->first()];
        }

Answer 2

您需要从获取用户的问题和答案开始，而不是从问题本身开始，以获得预期的输出：

$user = User::select('id','name','picture')->with([
            'questions' => function($query){
                $query->select('id','user_id','title','video','status','created_at');
                $query->where('status','>=','2');
            },
            'questions.answers' => function($query){
                $query->select('id','question_id','user_id','answer','created_at',DB::raw('count(*) as answer_count'));
                $query->orderBy('created_at','desc')->first();

            },
        ])->findOrFail($user_id);

现在，您应该能够得到所有的问题，由给定的用户和他们的最新答案如下：

foreach($user->questions as $question) {
  $answer = $question->answers;
}