在使用GroupBy和分頁時獲取錯誤Eloquent

Question

我想使用雄辯讓我按照響應分組，並同時給我一個分頁響應（讓我鏈接到第二頁）。 我試圖做到這一點：

App\Eating::Where('student_id', 2)->orderBy('created_at', 'DESC')->groupBy(function ($row) { 
    return Carbon\Carbon::parse($row->created_at)->format('Y-m-d'); 
})->paginate(25); 

但是，我得到的補鍋匠運行時，它這個錯誤：

PHP warning: strtolower() expects parameter 1 to be string, object given in D:\Folder\vendor\laravel\framework\src\Illuminate\Database\Grammar.php on line 58 

沒有GROUPBY，我得到正確的結果：

>>> App\Eating::Where('student_id', 2)->orderBy('created_at', 'DESC')->paginate(25)->toArray(); 
=> [ 
    "total" => 1, 
    "per_page" => 25, 
    "current_page" => 1, 
    "last_page" => 1, 
    "next_page_url" => null, 
    "prev_page_url" => null, 
    "from" => 1, 
    "to" => 3, 
    "data" => [ 
     [ 
     "id" => 5, 
     "status" => "Comeu Bem", 
     "created_at" => "2017-07-05 13:55:25", 
     "updated_at" => "2017-07-05 13:55:25", 
     ], 
    ], 
    ] 

但是，當我刪除了分頁，我得到的錯誤，但僅僅是因爲我加入了get（）方法：

>>> App\Eating::Where('student_id', 2)->orderBy('created_at', 'DESC')->groupBy(function ($row) { 
...       return Carbon\Carbon::parse($row->created_at)->format('Y-m-d'); 
...      })->get(); 
PHP warning: strtolower() expects parameter 1 to be string, object given in D:\Joao\git\F1Softwares\Code\Server\F1Softwares\vendor\laravel\framework\src\Illuminate\Database\Grammar.php on line 58 
>>> 
>>> 
>>> App\Eating::Where('student_id', 2)->orderBy('created_at', 'DESC')->groupBy(function ($row) { 
...       return Carbon\Carbon::parse($row->created_at)->format('Y-m-d'); 
...      }); 
=> Illuminate\Database\Eloquent\Builder {#855} 

任何想法我可能做錯了什麼？我需要有orderBy和分頁，讓應用更容易顯示結果（這是一個RestFul調用）。

感謝， 若昂

Answer 1

您必須調用一個集合groupBy()方法，但似乎這並不會與paginate()工作。你可以嘗試使用forPage()方法的集合：

App\Eating::where('student_id', 2)->orderBy('created_at', 'DESC') 
    ->get()->groupBy(function ($eating) { 
     return $eating->created_at->format('Y-m-d'); 
    })->forPage(1, 25); 

而且，只是一個說明，你不需要用碳來解析日期，雄辯做這個給你。

---

或者，你可以嘗試manually create your paginator一旦你使用Illuminate\Pagination\LengthAwarePaginator分組的集合。

$eatings = App\Eating::where('student_id', 2)->orderBy('created_at', 'DESC') 
       ->get()->groupBy(function ($eating) { 
        return $eating->created_at->format('Y-m-d'); 
       }); 
$paginatedEatings = new LengthAwarePaginator($eatings, $eatings->count(), 25); 

return $paginatedEatings->toArray();