用户有一个扩展表 profiles, 每个用户对应一个 profile 的一条记录

1).User.php 添加代码

  public function profile ()
    {
      // 要有外键 user_id
       return $this->hasOne (Profile::class)->select (["user_id","phone"]);
    }

2. 测试代码

   Artisan::command ('linson:query',function (){DB::enableQueryLog ();
   
   // Run your queries
   // 要有 id 主键，不然无法查询 profile
   $res = \App\User::with ('profile')->first (["id"]);
   print_r ($res->toArray ());
   // Then to retrieve everything since you enabled the logging:
   $queries = DB::getQueryLog ();
   foreach ($queries as $i=>$query)
   {Log::debug ("Query $i:" . JSON_encode ($query));
   }
   });