xixie/application/common/model/ChinaArea.php

<?php
namespace app\common\model;
use think\Model;
// 地址管理
class ChinaArea extends Model
{
    public static function getAllCity()
    {
        $all_first = self::field('first')->order('first asc')->group('first')->select()->toArray();
        array_walk($all_first,function (&$v,$k){
            $v['city_list'] = self::field('id,name,short_name')->where(['first'=>$v['first'],'level'=>2])->select()->toArray();
        });
        return  $all_first;
    }

}