这个怎么改才对？？？

Question

<?php

header("Content-type:text/html;charset=utf-8");

if ($con = mysqli_connect('localhost','root','838814993')){

  echo"链接成功\n";

}else{

  echo"连接失败\n";

}

$query = mysqli_query($con,'select * from category');

mysqli_fetch_row($query);

Answer 1

看提示，$data,$dbc变量都没有声明,