Can I have 2 header locations in PHP? - php

Question

So, I know my code was working and I have tried un-doing all steps to see where the bug is, but I am still keep getting an error
my php id=0.
Can you guys show me how I can fix my code up?
The error is as follows:
undefined variable list_id. It works on my localmachine but not when
uploaded to server.
Thanks.
The following is my code:
if(!empty($_GET['id'])){
$list_id = intval(($_GET['id']));
try {
$sql = 'SELECT * FROM items where id =' . $list_id;
$query = $pdo->prepare($sql);
$query->execute();
} catch(Exception $e) {
echo $e->getMessage();
die();
}
$list = $query->fetch(PDO::FETCH_ASSOC);
if ($list == FALSE) {
header("location: index.php");
}
}
if ($list_id == 0) {
header("location: index.php");
}

Answer 1

Seems there are a few issues here. I have added the comments inline.
if(!empty($_GET['id'])){
$list_id = intval($_GET['id']); //was double parenthesis here
try {
$sql = 'SELECT * FROM items where id =' . $list_id;
$query = $pdo->prepare($sql);
$query->execute();
} catch(Exception $e) {
echo $e->getMessage();
die();
}
$list = $query->fetch(PDO::FETCH_ASSOC);
$count = count($list); //count result and use for comparison instead of false
if ($count === 0) {
header("location: index.php");
exit;
}
} else {
header("location: index.php"); //if no $_GET, redirect
exit;
}

Answer 2

All you need to do is instantiate the variable $list_id :
$list_id = 0; // <-- HERE
if(!empty($_GET['id'])){
$list_id = intval(($_GET['id']));
...
...

Answer 3

It looks as though you want to redirect to the index if there is no id parameter. Since you already check for its presence, redirect in the else clause. Remove the last block and add:
else
{
header("location: index.php");
exit;
}
You may want to add exit; after the header() call in the if block as well, so that code that uses the database further down isn't executed.