After mysqli_connect(); gives the penultimate value, session reset?

Question

MySQL

Just PHP
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include ABSPATH . "/ns-connect.php";
  $result     = mysqli_query($connection, "SELECT * FROM `wp_ign_pay_info` ORDER BY `id` DESC");

  // Getting product_id
  $last_order = mysqli_fetch_assoc($result);
  $product_id = $last_order['product_id'];

  // Getting product_title
  $query_product_title = mysqli_query($connection, "SELECT * FROM `wp_ign_products` WHERE `id` = $product_id");
    $product_name        = mysqli_fetch_assoc($query_product_title);
    $project_name        = $product_name['product_name'];

WordPRess way
=============================================== ==================

global $wpdb;

$latest_order = $wpdb->get_results("SELECT * FROM `wp_ign_pay_info` ORDER BY `id` DESC LIMIT 1");
$txn_id = $latest_order[0]->transaction_id;

$result = $wpdb->get_results("SELECT * FROM `wp_ign_pay_info` WHERE `transaction_id` = '$txn_id'");
$product_id = $result[0]->product_id;

$query_product_title = $wpdb->get_results("SELECT * FROM `wp_ign_products` WHERE `id` = $product_id");
$product_name = $query_product_title[0]->product_name;

Then I request the necessary parameters through wp-functions, but after the second time, the script starts giving me the penultimate entry by id, instead of the last one.
If it (a request with data) was in the last session, then the request issues the next one in descending order.
Question: How to properly reset a session or request?
And would each time to receive the last record in the table?
Thank you.