lanzu_api_2021-12-26/app/Model/v3/CouponRec.php

<?php

namespace App\Model\v3;

use App\Model\Model;

class CouponRec extends Model
{

    protected $table = 'lanzu_coupon_receive';

    protected $appends = [
        'used_num'
    ];

    public function getUsedNumAttribute()
    {
        return ($this->attributes['number'] - $this->attributes['number_remain']);
    }

    public function coupon()
    {
        return $this->hasOne(Coupon::class,'id','coupon_id');
    }
}