对关系进行雄辩的模型排序（一个>很多）

Question

I've got a model called "Lesson" which has a ->hasMany() relationship which represent the dates for this lesson.

To retrieve every lesson with a date within a certain time-span I use a whereHas :

$list = Lesson::whereHas('dates', function ($query)  use ($start, $end) {
   $query->where('date','>=', $start->format('Y-m-d'))
         ->where('date','<=', $end->format('Y-m-d'));
})->get()

This works as expected, but I now want to sort the $list by the 'smallest' date associated with the lesson.

Preferably I wish to use the Eloquent models, as there are some needed methods in the model. But if it's not possible, than a 'plain' sql statement could also be used.

Answer 1

You can use the available methods of Laravel collections .This code should do it.

$sortedLessons = $lessons->sortBy(function ($lesson) {
    $dates = $lesson->dates;
    $minDate = $dates->sortBy('date');
    return $minDate;
});

I assumed that you have a field date in your date model.