在对 Laravel 中的值求和后如何从高到低排序？

Question

我是 Laravel 的新手。现在，我很难根据学生的总分从高到低对学生的名字进行排序。以下是我从邮递员那里得到的数据。

{ 
  "score": [
    {
        "name": "Adam",
        "sex": "male",
        "totalMarks": 250
    },
    {
        "name": "Lisa",
        "sex": "female",
        "totalMarks": 350
    },
    {
        "name": "Daniel",
        "sex": "male",
        "totalMarks": 300
    },
    {
        "name": "Mary",
        "sex": "female",
        "totalMarks": 330
    },
    {
        "name": "Sarah",
        "sex": "female",
        "totalMarks": 280
    }
  ]
}

下面是我的 ScoreController.php 代码

$class_id = $user->class->id;
$students = Students::whereIn('class_id', $class_id)->get();
$score = array();

foreach ($students as $student) {
   array_push($score, [
      'name' = $student->name,
      'sex' = $student->sex,
      'totalMarks' = $student->subjects->sum('mark'),
   ]);
}

return response()->json([
  'score' => $score,
]);

我想根据mark 的总和对学生进行排序。所以totalMarks 最高的学生应该在列表的顶部。提前谢谢你。

Answer 1

在这里使用雄辩的属性可能对你有好处。在你的学生类中添加一个雄辩的mutator。

class Students {
    // to include it in the response.
    $with = ['totalMarks'];

    public function getTotalMarksAttribute() {
        return $this->subjects->sum('mark');
    }
}

现在您可以稍微优化您的原始代码。使用这种方法，您不必将对象转换为数组。

$students = Students::whereIn('class_id', $class_id)
    ->get()
    ->sortByDesc('totalMarks');

// laravel will automatic transform the objects, an way more maintainable approach
return response()->json([
  'score' => $students,
]);