Laravel Eloquent另一个表中的列的总和

Question

所以我有这个输出：

以下是我的控制器中的代码：

public function showToday()
    {
        $now = new DateTime('today');
        $today = $now->format('Y-m-d');
        $reservations = Reservation::with('room') ->where('reservation_from', $now)
                                                            ->orderBy('created_at')
                                                            ->get();

        return \View::make('pages.admin.report.today') -> with('reservations', $reservations)
                                                       -> with('now', $today);
    }

架构：

查看（刀片）

  <div class="box-body table-responsive no-padding">
    <table class="table table-bordered">
      <thead>
        <tr>
          <th>Room #</th>
          <th>Reservation From</th>
          <th>Reservation To</th>
          <th>Booked At</th>
          <th>Amount</th>
      </thead>
      </tr>
      <tbody>
        @foreach($reservations as $res)
        <tr>
          <td>{{ $res -> room -> room_number }}</td>
          <td>{{ date('F d, Y', strtotime($res -> reservation_from)) }}</td>
          <td>{{ date('F d, Y', strtotime($res -> reservation_to)) }}</td>
          <td>{{ $res -> created_at }}</td>
          <td>{{ $res -> room -> price }}</td>
        </tr>
        @endforeach
        <tr>
          <td colspan="2"><strong>Total:</strong></td>
          <td></td>
          <td></td>
          <td></td>
          <td><!-- Display price total here --></td>
        </tr>
      </tbody>
    </table>
  </div>

预订模式

class Reservation extends Model
{
    use SoftDeletes;
    protected $table = 'reservations';

    protected $fillable = ['roomNumber', 'clientId', 'reservation_from', 'reservation_to'];

    public function room() {
        return $this->belongsTo('App\Room');
    }

}

会议室模型

class Room extends Model
{
    use SoftDeletes;
    protected $table = 'rooms';

    protected $fillable = ['id', 'roomNumber', 'type', 'price', 'description'];

    public function reservations() {
        return $this->hasMany('App\Reservation', 'id', 'room_number');
    }
}

当我尝试在我的控制器中添加它时，

$sum = $reservations['room']->sum( 'price' );
dd($sum);

我得到Undefined index: room

我想要的是通过添加房间表中的价格来显示总金额（总和）。我怎么能用Laravel和Eloquent做到这一点？提前谢谢。

Answer 1

$reservations->sum('room.price')