order by cast(score as int) desc

$servername = "localhost";
$username = "tabulati_user";
$password = "Star51@#";
$dbname = "tabulati_ats";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

$catId = $Categories->id;
$sqlRank = "SELECT *  FROM rankings where catId='".$catId."' and judId='".$judgeId."' order by cast(score as int) desc";
$resultRank = $conn->query($sqlRank);