title: Eloquent query order by problem: always return SQLSTATE[23000]: Integrity constraint violation: 1052
body: <p>I write down this scope in voyager</p>
  <pre><code>        return Auth::user()-&gt;hasRole('user') ? $query
                                -&gt;where('employees.client_id', Auth::user()-&gt;client_id)
                                -&gt;join('employees', 'formations.employee_id', '=','employees.id')
                                : $query;
  
  but it return the following error
  </code></pre>
  <p>SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'created_at' in order clause is ambiguous (SQL: select * from <code>formations</code> inner join <code>employees</code> on <code>formations</code>.<code>employee_id</code> = <code>employees</code>.<code>id</code> where <code>employees</code>.<code>client_id</code> = 111 order by <code>created_at</code> desc)</p>
  <pre><code>then I change it to 
          return Auth::user()-&gt;hasRole('user') ? $query
                            -&gt;where('employees.client_id', Auth::user()-&gt;client_id)
                            -&gt;join('employees', 'formations.employee_id', '=', 'employees.id')
                             -&gt;orderBy('employees.created_at','DESC')
                             : $query;
  </code></pre>
  <p>and I got this error</p>
  <pre><code>
  SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'created_at' in order clause is ambiguous 
  (SQL: select * from `formations` inner join `employees` on `formations`.`employee_id` = employees`.`id` where `employees`.`client_id` = 111 order by `employees`.`created_at` desc, `created_at` desc)
  
  </code></pre>
  <p>it seem to me laravel need to put any default. Is it a bug? Can i fix somehow?</p>