$_SESSION variables always printing 'S' and not intended variable when set [duplicate] - php

Question

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MySQL query pulling one row and displaying first letter of result
(3 answers)
Closed 3 years ago.
<?php
if($_POST)
{
include 'config.php';
$referencenumber=$_POST['reference_number'];
$fullname=$_POST['full_name'];
$sRef=mysqli_real_escape_string($conn,$referencenumber);
$sName=mysqli_real_escape_string($conn,$fullname);
$query="SELECT * From customers where reference_number='$sRef' and
full_name='$sName'";
$result=mysqli_query($conn,$query);
if(mysqli_num_rows($result)==1)
{
session_start();
$_SESSION['id'] = $query['id'];
$_SESSION['refnumber'] = $query['reference_number'];
header('location:index.php');
}
}
?>
The above code is what I have written on my login.php page. After a successful login, the user arrives at the index.php page.
var lz_data = {overwrite:true,111:'<?php
print_r($_SESSION['refnumber'])?>',
I am then attempting to print the reference number on the next page here, which will set a value that matches the one in $_SESSION['refnumber'] but for some reason the output of this code always seems to be 'S' when printing, just the letter S. I get the same output when I try to print $_SESSION['id'] as well. Any ideas?
EDIT: session_start(); has been added at the start of index.php, and the double quotations didn't solve the issue.

Answer 1

You try to get a specific index of a string instead of the result / row array:
$query="SELECT * From customers where reference_number='$sRef' and full_name='$sName'";
$_SESSION['id'] = $query['id']; // $query is a string not an array.
$_SESSION['refnumber'] = $query['reference_number']; // $query is a string not an array.
Why you only get "S" on the session?
You can use a string value on PHP like an array. So you can use $query[0] to get the "S" and $query[1] to get the "E" and so on. In your case the $query['id'] is the same like $query[0] because var_dump('id' == 0) is true.
demo on ideone.com
How to solve this?
You can use the mysqli_result::fetch_array method to get the row with columns as index from $result:
//get the $row from $result with fetch_array.
$row = $result->fetch_array(MYSQLI_ASSOC);
//now you can use the row array to set the values to the session.
$_SESSION['id'] = $row['id'];
$_SESSION['refnumber'] = $row['reference_number'];
So your code looks like the following:
<?php
if($_POST) {
include 'config.php';
$referencenumber = $_POST['reference_number'];
$fullname = $_POST['full_name'];
$sRef = mysqli_real_escape_string($conn, $referencenumber);
$sName = mysqli_real_escape_string($conn, $fullname);
$query = "SELECT * From customers where reference_number='$sRef' and full_name='$sName'";
$result=mysqli_query($conn, $query);
if(mysqli_num_rows($result) == 1) {
//get the $row from $result with fetch_array.
$row = $result->fetch_array(MYSQLI_ASSOC);
session_start();
$_SESSION['id'] = $row['id'];
$_SESSION['refnumber'] = $row['reference_number'];
header('location:index.php');
}
}