php 根据经纬度查询距离

$having = 'distance <= 5000'
$merch_store_info = db('merch_store')
                                ->alias('ms')
                                ->join('merch_cate mc','ms.cateid = mc.id','left')
                                ->join('merch_sign sn','ms.sign_id = sn.id','left')
                                ->where($where)
                                ->field("ms.id,name,ms.business_time,ms.business_time_start,ms.business_time_end,ms.head_img,ms.address,ms.sales_count,mc.title as cate_name,sn.title as sign_name,sn.color,ms.lng,ms.lat,(6378.138 * 2 * asin(sqrt(pow(sin((lat * pi() / 180 - ".$lat." * pi() / 180) / 2),2) + cos(lat * pi() / 180) * cos(".$lat." * pi() / 180) * pow(sin((lng * pi() / 180 - ".$lng." * pi() / 180) / 2),2))) * 1000) as distance")
                                ->having($having)
                                ->order($sort)
                                ->page($page, $pagesize)
                                ->select();