Question

我的代码

$result=DB::table('receipts')
      ->join('dealer_m','receipts.ToDealerID','dealer_m.DealerID')
      ->join('dealer_m','receipts.FromDealerID','dealer_m.DealerID')
      ->join('product_m','receipts.ProductID','product_m.ProductID')->get();

餐桌收据

Id | FromDealerId  | ToDealerId  |  ProductId
---+---------------+-------------+------------
1         1              2            1

2         1              3            1

3         3              1            1

桌子经销商_m

DealerId | DealerName    
---------+-----------
  1         Dealer One
  2         Dealer Two
  3         Dealer Three

表product_m

ProductId | ProductName
----------+-----------
    1       Product One
    2       Product Two

预期产量

Id | FromDealerId  | ToDealerId  |  ProductId | FromDealerName | ToDealerName | ProductName
---+---------------+-------------+------------+----------------+--------------+------------


 1         1              2            1         Dealer One      Dealer Two  Product One

 2         1              3            1         Dealer One      Dealer Three  Product One

 3         3              1            1         Dealer Three    Dealer One   Product One

我运行代码时出现错误

SQLSTATE [42000]：语法错误或访问冲突：1066不是唯一的表/别名：'dealer_m'（SQL：从'receipts'内部联接中选择' '收据'上的'dealer_m'。'ToDealerID'='dealer_m'。'DealerID'内部在'receipts'上加入'dealer_m'。'FromDealerID'='dealer_m'。'DealerID' 内部联接'收据'上的'product_m'。'ProductID'= 'product_m'。'ProductID'）

如何解决这个问题？

谢谢

Answer 1

尝试一下：

$results=DB::table('receipts')
      ->select('receipts.*','dealer_m1.DealerName as ToDealer','dealer_m2.DealerName as FromDealer','product_m.ProductName')
      ->join('dealer_m as dealer1','receipts.ToDealerID','dealer_m.DealerID')
      ->join('dealer_m as dealer2','receipts.FromDealerID','dealer_m.DealerID')
      ->join('product_m','receipts.ProductID','product_m.ProductID')->get();

您只需要给每个联接表一个别名

现在在您的刀片中：

@foreach ($results as $result)
  <tr>
    <td>{{$result->Id}}</td>
    <td>{{$result->FromDealerId}}</td>
    <td>{{$result->ToDealerId}}</td>
    <td>{{$result->ProductId}}</td>
    <td>{{$result->FromDealer}}</td>
    <td>{{$result->ToDealer}}</td>
    <td>{{$result->ProductName}}</td>
  </tr>
@endforeach

当然，如果您卡在刀片中调用什么，只需打印我们的集合以找到键=>值或执行dd（$ results）;在控制器中进行检查，然后再进入视图。

Answer 2

您应该尝试以下操作：

$result=DB::table('receipts')
      ->join('dealer_m as dealer_id','receipts.ToDealerID','dealer_m.DealerID')
      ->join('dealer_m as dealer_f_id','receipts.FromDealerID','dealer_m.DealerID')
      ->join('dealer_m as product_p_id','receipts.ProductID','product_m.ProductID')->get();

Laravel连接查询与同一表中的两列

2 个答案:

尝试一下：