wordpress template page error when select from database

I have take the page.php page and i have created a new template page named mytemplatepage.php The page mytemplatepage.php works normally untill i try to add an sql query. when i add the bellow code the page gives http 500 error.

<?php
 global $wpdb;
  $sqlresults = $wpdb->get_results(
        "SELECT id, CategoryName
        FROM wp_SimParts"
        );
 ?>

if i remove the code and just leave

<?php
?>

the page load normally. if i put an echo on the php code the page again crashes with http 500 error

<?php
echo "hello there";
?>