Laravel Eloquent:如何排序相关模型的结果?

Laravel Eloquent: How to order results of related models?(Laravel Eloquent:如何排序相关模型的结果?)

问题描述

我有一个名为School的模型，它有很多学生.

I have a model called School and it has many Students .

这是我模型中的代码:

public function students()
{
    return $this->hasMany('Student');
}

我正在让所有学生在我的控制器中使用此代码:

I am getting all the students with this code in my controller:

$school = School::find($schoolId);

在视图中:

@foreach ($school->students as $student)

现在我想按 students 表中的某个字段对 Students 进行排序.我该怎么做?

Now I want to order the Students by some field in the students table. How can I do that?

推荐答案

你有几种方法可以实现:

You have a few ways of achieving this:

// when eager loading
$school = School::with(['students' => function ($q) {
  $q->orderBy('whateverField', 'asc/desc');
}])->find($schoolId);

// when lazy loading
$school = School::find($schoolId);
$school->load(['students' => function ($q) {
  $q->orderBy('whateverField', 'asc/desc');
}]);

// or on the collection
$school = School::find($schoolId);
// asc
$school->students->sortBy('whateverProperty');
// desc
$school->students->sortByDesc('whateverProperty');


// or querying students directly
$students = Student::whereHas('school', function ($q) use ($schoolId) {
  $q->where('id', $schoolId);
})->orderBy('whateverField')->get();

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