<?php
    $secret_key = filter_input(INPUT_POST, 'secret_key');
    if(empty($secret_key)):
        echo "Necessary field is empty, please fill it";
        die();

    $host = "localhost";
    $dbusername = "root";
    $dbpassword = "";
    $dbname = "aniket";
    // Create connection

    mysql_connect($host, $dbusername, $dbpassword);
    mysql_select_db($dbname);
    $sql = "SELECT enrollment_no from secret_keys WHERE secret_key='$secret_key'";
    $result = mysql_query($sql) or die(mysql_error());
    echo "Enrollment Number: ".$result;
?>