app-api/app/Models/Course/Course.php

<?php

namespace App\Models\Course;

use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Database\Eloquent\Model;
use DateTimeInterface;
use Carbon\Carbon;

class Course extends Model
{
    use SoftDeletes;
    protected $connection = 'mysql_c';
    protected $table='course';
    protected $guarded=[];
    protected $appends = ['create_at_humans'];

    public static $courseLevel = [
        '1' =>[1],
        '2' =>[2],
        '3' =>[3],
        '4' =>[1,2],
        '5' =>[1,3],
        '6' =>[2,3],
        '7' =>[1,2,3],
    ];

    public static $levelCourse = [
        '1' =>[1,4,5,7],
        '2' =>[2,4,6,7],
        '3' =>[3,5,6,7],
    ];

    public function getImgAttribute($value)
    {
        return json_decode($value,'true');
    }
    public function getAudioAttribute($value)
    {
        return json_decode($value,'true');
    }
    public function getVideoAttribute($value)
    {
        return json_decode($value,'true');
    }

    protected function serializeDate(DateTimeInterface $date): string
    {
        return $date->format('Y-m-d H:i:s');
    }

    public function getCreateAtHumansAttribute($key)//此处的Pic与追加字段'pic' 相对应
    {
        return Carbon::createFromFormat('Y-m-d H:i:s', $this->attributes['created_at'])->diffForHumans();
    }
//    public function getCreatedAtAttribute($value){
//        return Carbon::createFromFormat('Y-m-d H:i:s', $value)->diffForHumans();
//    }
    public static function setField()
    {
        return self::query()->select('id',
            'title',
            'is_share',
            'cate',
            'perface',
            'img',
            'video',
            'audio',
            'c_id',
            'avatar',
            'author',
            'permission',
            'is_top',
            'top_at',
            'state',
            'collection',
            'share',
            'comms',
            'created_at',
            'updated_at');
    }
}