mysql - Laravel 连接多个表

Question

我有 3 个 mysql 表

**Clients**  
id | name 

**Services**
id | name | foreign key -> client_id

**Payments**  
id | payment_date | amount | foreign key -> service_id  

客户端 Controller .php

$sumPayments = Payment::join('services', 'payments.service_id', '=', 'services.id')
        ->join('clients', 'clients.id', '=', 'services.client_id')->get();

客户端/index.blade.php

@foreach($clients as $client)
      <tr>  
@foreach($service->payments as $payment)
          @if($payment->service_id == $service->id)
            <td>{{$sumPayments->where('service_id', '$services->id')->sum('payment_amount')}}</td>
            @break
          @endif
        @endforeach   
  </tr>
@endforeach  

我的模型中有 'belongsTo' 和 'hasMany'。
我尝试显示每个客户已支付的总付款额。请帮忙。

Answer 1

使用 withCount()方法:

Client::withCount('payments')->get();

f you want to count the number of results from a relationship without actually loading them you may use the withCount method, which will place a {relation}_count column on your resulting models.

因此，此代码将为每个客户端创建一个新的 payments_count 属性:

@foreach ($clients as $client)
    {{ $client->payments_count }}
@endforeach