如何从数据库访问used_id ?

Question

警告:试图访问D:xampphtdocs电子商务网站users_areapayment.php第34行中null类型值的数组偏移

我试图从数据库访问users_id，但我得到这个错误消息

<?php
$user_ip=getIPAddress();
$get_user="select * from `user_table` where user_ip='$user_ip'";
$result=mysqli_query($con,$get_user);
$run_query=mysqli_fetch_array($result);
$user_id=$run_query['user_id'];
?>
<div class="container">
<h2 class="text-center text-info">payment options</h2>
<div class="row d-flex justify-content-center align-items-center my-5">
<div class="col-md-6">
<a href="https://www.paypal.com" target="_blank"><img src="../assets/photos/paypal.jpg" alt=""></a>
</div>
<div class="col-md-6">
<a href="order.php?user_id=<?php echo $user_id ?>"><h2 class="text-center">pay offline</h2></a>
<!-- <a href="order.php"><h2 class="text-center">pay offline</h2></a> -->
</div>

Answer 1

你可以试试这个

$sql = "select * from `user_table` where user_ip='$user_ip'";
$result = $mysqli -> query($sql);
// Numeric array
$row = $result -> fetch_array(MYSQLI_NUM);
printf ("%s (%s)n", $row[0], $row[1]);
// Associative array
$row = $result -> fetch_array(MYSQLI_ASSOC);
printf ("%s (%s)n", $row["user_id"]);