Laravel 5.1用（）和max（）使用多重关系多数人关系

Question

我试图用Eloquent在多重关系的最后一个表上找到列的最大值。

给出下面的表格结构。

建筑

+----+---------------+ 
| id | building_name | 
+----+---------------+ 
| 1 | Building 1 | 
| 2 | Building 2 | 
+----+---------------+ 

客房

+----+-----------+-------------+ 
| id | room_name | building_id | 
+----+-----------+-------------+ 
| 1 | Room 1 |   1 | 
| 2 | Room 2 |   1 | 
| 3 | Room 3 |   2 | 
+----+-----------+-------------+ 

maintenancelog

+----+-------------------+---------+---------------------+ 
| id | maintenance_value | room_id |  timestamp  | 
+----+-------------------+---------+---------------------+ 
| 1 | Cleaned   |  1 | 2015-09-06 00:54:59 | 
| 2 | Cleaned   |  1 | 2015-09-06 01:55:59 | 
| 3 | Cleaned   |  2 | 2015-09-06 02:56:59 | 
| 4 | Cleaned   |  2 | 2015-09-06 03:57:59 | 
| 5 | Cleaned   |  3 | 2015-09-06 04:58:59 | 
| 6 | Cleaned   |  3 | 2015-09-06 05:59:59 | 
+----+-------------------+---------+---------------------+ 

我想看看是否有可能生成将检索建筑物名称的雄辩的发言，房间名称和仅最后一个维护日志日期值。

下面的工作给我一个所有值的集合。

$buildings = Building::with('rooms.maintenancelog')->get(); 

但这样的错误了，它看起来像它试图在建筑物表调用MAX（maintenancelog.timestamp）..

$buildings = Building::with('rooms.maintenancelog')->max('maintenancelog.timestamp')->get(); 

返回错误：

.....(SQL: select max(`maintenancelog`.`timestamp`) as aggregate from `buildings`) 

上午我只是从雄辩中提出太多问题，应该只使用基本查询构建器

Answer 1

将以下关系onship的房间模型...

public function latestMaintenance() 
{ 
    return $this->hasOne('App\Maintenancelog')->latest(); 
} 

，改变雄辩的发言，以..

$buildings = Building::with('rooms.latestMaintenance')->get(); 

引用Getting just the latest value on a joined table with Eloquent