Untitled

$servername = "localhost";
    $username = "root";
    $password = "root";
    $dbname = "myDB";


    $conn = new mysqli($servername, $username, $password, $dbname);

    if ($conn->connect_error) {
         die("Connection failed: " . $conn->connect_error);
    }

    $sql = "SELECT id, firstname, lastname FROM tablenamehere  ORDER BY id DESC LIMIT 500";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {

         while($row = $result->fetch_assoc()) {
             echo "<p>". $row["firstname"]. " " . $row["lastname"] . "</p>";
         }
    } else {
         echo "0 results";
    }

    $conn->close();

$sql = "SELECT id, firstname, lastname FROM tablenamehere  ORDER BY id DESC LIMIT 500";
    $result = $conn->query($sql);

<html>
<body>
<a href="test1.php?a=newtable">Register Now!</a>
</body>
</html>
<?php

session_start();
?>

<?php
 if(isset($_GET['a'])){
    $_SESSION['link']=$_GET['a'];
 }

 echo "the veriable is " . $_SESSION['link'] . "<br>";

$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "myDB";
$tablename = $_GET['a'];


$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
     die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT id, firstname, lastname FROM $tablename ORDER BY id DESC LIMIT 500";
$result = $conn->query($sql);

<?php

if(isset($_GET['a'])){
    $_SESSION['link']=$_GET['a'];
}


$sql = "SELECT id, firstname, lastname
        FROM {$_SESSION['link']}
        ORDER BY id
        DESC LIMIT 500";

if(isset($_GET['a'])){
    $_SESSION['link']=$_GET['a'];
}


switch ($_SESSION['link']) {
case : 'a'
    $tbl_name = 'table1';
    break;
case : 'b'
    $tbl_name = 'table2';
    break;
default:
    $tbl_name = 'default_table';
}


$sql = "SELECT id, firstname, lastname
        FROM $tbl_name
        ORDER BY id
        DESC LIMIT 500";