laravel Lazy Eager正在加载orderBy相关模型

问题描述：

I need to lazy eager load some related models with custom order. Something like:

$season->load(['championships' => function ($query) {
    $query->orderBy('country', 'desc');
}]);

But the problem is that championships do not have country property. In Championship model I use getCountryAttribute function:

public function getCountryAttribute()
{
    return $this->masterChampionship->country;
}

public function masterChampionship()
{
    return $this->belongsTo('App\MasterChampionship');
}

And I get next results:

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'country' in 'order clause' (SQL: select * from `championships` where `championships`.`season_id` in (41) order by `country` desc)

If i don't use load in controller and access championships from blade template

@foreach($season->championships->sortBy('country') as $championship)
    ....
@endforeach

everything works fine. But I want to cleanup template and move logic to controller. Is there any possibility to solve my case using built-in laravel features, without building custom BD query.

我需要懒得加载一些带有自定义顺序的相关模型。类似于： p>

  $ season-＆gt; load（['championships'=＆gt; function（$ query）{
 $ query-＆gt; orderBy（'country'，  'desc'）; 
}]）; 
  code>  pre> 
 
 但问题是锦标赛没有乡村财产。 在锦标赛模型中，我使用getCountryAttribute函数： p> 
 
 
  public function getCountryAttribute（）
 {
返回$ this-＆gt; masterChampionship-＆gt; country; 
} 
 \  npublic function masterChampionship（）
 {
返回$ this-＆gt; belongsTo（'App \ MasterChampionship'）; 
} 
  code>  pre> 
 
 我得到下一个结果 ： p> 
 
 
  SQLSTATE [42S22]：未找到列：1054'order clause'中的未知列'country'（SQL：从`championships`中选择*，其中`championships``  season_id` in（41）order by`sountry`desc）
  code>  pre> 
 
 如果我不在控制器中使用加载 strong>并从中获取锦标赛 刀片模板 p> 
 
 
  @foreach（$ season-＆gt; championships-＆gt; sortBy（'country'）as $ championship）
 .... 
 @ endforeach 
   code>  pre> 
 
 一切正常。 但我想清理模板并将逻辑移动到控制器。 是否有可能使用内置的laravel功能解决我的情况，而无需构建自定义BD查询。 p> 
  div>

答

Youll have to change the table names, as I don't know what they are, but I think this would work:

$season->load(['championships' => function($query){

    $query->select('championships.*')
        ->join('master_championships', 'championships.master_championships_id', '=', 'master_championships.id')
        ->orderBy('master_championships.country', 'desc');

}]);

I don't think you can order the query without using a join, seeing as you have to access the third table to get the country attribute. You may save a bunch of queries from hitting the database if you do

$season->load(['championships','championships.masterChampionships']);

laravel Lazy Eager正在加载orderBy相关模型

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