Mysql compare two table

         $allCount = $this->mysqli->query("select count(*) from auth");
         $allCount = $allCount->fetch_assoc()["count(*)"];
         for ($i = 0; $i < $allCount; $i++){
             $player = ($this->mysqli->query("select `login` from `auth` limit $i, 1")->fetch_assoc())['login'];
             $issetPlayer = $this->mysqli->query("select `login` from `data` where `login` = '$player'");
             if ($issetPlayer->num_rows < 1){
                //return (var_dump($player, $i, $issetPlayer));
                $this->mysqli->query("INSERT INTO `data`(login) VALUES('$player')");
             }


         }