Error while running UPDATE

Question

When executing the UPDATE the following errors occurred:

Notice: Undefined variable: mysqli in C:\xampp\htdocs\guaraparivirtual\count\count.php on line 17

Fatal error: Uncaught Error: Call to a member function query() on null in C:\xampp\htdocs\guaraparivirtual\count\count.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\guaraparivirtual\count\count.php on line 17

Code:

 <?php include ("../incluir/conexao.php"); ?>

<?php
$id = $_GET["id"];


                $propaganda_count=mysqli_query($con,"select click,link FROM bannersclick where id='$id'");
                while($count_click=mysqli_fetch_array($propaganda_count)){

                    $clickget = $count_click['click'];
                    $linkget = $count_click['link'];
                }

$clickget = $clickget + 1;

    $sqli = "UPDATE bannersclick SET click = '$clickget' where id = '$id'";
    $mysqli->query($sqli);

header( "Location: $linkget" , TRUE , 302 );
?> 

Line 17 of the errors is: $mysqli->query($sqli);

I tried to solve, but did not understand the reason for the error.

Answer 1

From the error, it seems that no connection was started in the variable $mysqli. And looking at the rest of the added code, the variable $mysqli does not exist until you use it in line 17, in the previous query, you use the variable $conn to do the research.

Without changing the code too much, instead of using a variable that does not exist, use the connection variable you used in the previous query:

<?php include ("../incluir/conexao.php"); ?>

<?php
    $id = $_GET["id"];

    $propaganda_count=mysqli_query($con,"select click,link FROM bannersclick where id='$id'");

    while($count_click=mysqli_fetch_array($propaganda_count)){
        $clickget = $count_click['click'];
        $linkget = $count_click['link'];
    }

    $clickget = $clickget + 1;

    $sqli = "UPDATE bannersclick SET click = '$clickget' where id = '$id'";
    $conn->query($sqli);

    header( "Location: $linkget" , TRUE , 302 );
?> 

Pay attention to what the documentation says:

It is possible to switch between Styles at any time. Mixing Both Styles is not Recommended for code Clarity and coding style reasons.

That is, it is not recommended to use both modes at the same time, for reasons of organization and clarity of code.

Source: PHP document