怎么把查询结果加入到count里

if($result){
    //echo "查询成功";
    while ($row = mysqli_fetch_array($result))
    {
    $user = new User();
    $user->id = $row["id"];
    $user->username = $row["username"];
    $user->age = $row["age"];
    $user->sex = $row["sex"];
    $user->phonenumber = $row["phonenumber"];
    $data[]=$user;
    }
    $sql_count = "SELECT COUNT(*) FROM test3";
    $a = mysqli_query( $link, $sql_count );
    $b = mysqli_fetch_assoc( $a );
    $json_sql = json_encode($b);

    $json = json_encode($data);//把数据转换为JSON数据.
   
    echo '{"code":0,"count":'.$json_sql.',"data":'.$json.'}';
    }else{
    echo "查询失败";
    }

前端框架就不显示页码

$json_sql改成：count($b);