PianoTime/app/Models/CheckCard.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class CheckCard extends Model
{
    protected $table = 'check_cards';

    protected $guarded = [];

    public function student()
    {
        return $this->belongsTo('App\Models\Student');
    }

    public function studentCourse()
    {
        return $this->belongsTo('App\Models\StudentCourse');
    }

    public function course()
    {
        return $this->belongsTo('App\Models\Course');
    }

    public function getDuration()
    {
        $res = '';
        if(!empty($this['begin_date_time']) && !empty($this['end_date_time'])) {
            $begin_time = strtotime($this['begin_date_time']);
            $end_time = strtotime($this['end_date_time']);
            dd($end_time - $begin_time);
            if($end_time > $begin_time) {
                $diff_time = $end_time - $begin_time;
                $tmp = floor($diff_time / 3600);
                $diff_time = $diff_time % 3600;
                if(!empty($tmp)) {
                    $res .= $tmp . '小时';
                }
                $tmp = floor($diff_time / 3600);
                $diff_time = $diff_time % 60;
                if(!empty($tmp)) {
                    $res .= $tmp . '分钟';
                }
                if(!empty($diff_time)) {
                    $res .= $diff_time . '秒';
                }
                return $res;
            }
        }

        return $res;
    }
}