thinkphp分组查询,并查出每组最新数据

$subsql = Db::table('value_meter_yj_message')->where(['read'=>0])->field('equip_id,max(time) as time1,type')->group('equip_id,type')
        ->buildSql();
        $list=Db::table('value_meter_yj_message')
        ->alias('a')
        ->join([$subsql=> 'w'], 'a.equip_id = w.equip_id and a.time=w.time1')
        ->field('a.*')
        ->select();