注意未定义的偏移PHP

Question

如果管理员将页面更改为不可见，我正在尝试重定向页面，将可见值更改为零，我的代码出了什么问题，我一直收到错误

<?php
 $result = mysqli_query($con,"SELECT VISIBLE FROM  menu WHERE id=0");
 if($row = mysqli_fetch_array($result))
  {
 header('Location: ./unavailable.php? error=pagenotavaialbe');
 }
  else
 ?>

Answer 1

尝试这样的事情

$result = mysqli_query($con,"SELECT VISIBLE FROM  menu WHERE id=0");
if(mysqli_num_rows($result) == 0){
 header('Location: ./unavailable.php? error=pagenotavaialbe');
 exit;
} else {
 $row = mysqli_fetch_array($result);
//do your code here
}

Answer 2

试试这个：

if($result)
{ 
   if($row = mysqli_fetch_array($result)) 
   { 
      header('Location: ./unavailable.php? error=pagenotavaialbe'); 
   }
}