PianoTime/app/Imports/StudentsImport.php

<?php

namespace App\Imports;

use App\Models\Course;
use App\Models\Student;
use App\Models\StudentCourse;
use App\Models\StudentCourseTeacher;
use App\Models\Teacher;
use Carbon\Carbon;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\ToArray;
use Maatwebsite\Excel\Concerns\ToCollection;

class StudentsImport implements ToArray
{
    public function array(array $rows)
    {
        foreach($rows as $key => $row)
        {
            if($key == 0) continue;
            $student = Student::create([
                'name' => $row[0],
                'phone' => $row[1],
                'remark' => $row[6],
            ]);

            $course = Course::firstOrCreate([
                'name' => $row[2]
            ]);

            $assign_teacher = $row[5] == '全部' ? 1 : 2;

            $duration = null;
            if(!empty($row[3]) && !empty($row[4]) && $row[4] > $row[3]) {
                $duration = Carbon::createFromTimestamp(strtotime($row[3]))->diffInDays(Carbon::createFromTimestamp(strtotime($row[4])));
            }
            $student_course = StudentCourse::create([
                'student_id' => $student->id,
                'course_id' => $course->id,
                'apply_date' => $row[3],
                'duration' => $duration,
                'assign_teacher' => $assign_teacher
            ]);

            if($assign_teacher == 2) {
                $teacher_names = explode(',', $row[5]);
                foreach($teacher_names as $teacher_name) {
                    $teacher = Teacher::firstOrCreate([
                        'name' => $teacher_name
                    ]);

                    StudentCourseTeacher::create([
                        'student_course_id' => $student_course->id,
                        'teacher_id' => $teacher->id,
                        'student_id' => $student->id,
                    ]);
                }
            }
        }
    }
}