$sql = "SELECT user_type FROM usersTable WHERE (username = $user_name);
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);
$sth->execute() or die("Could not execute!" . $dbh->errstr);

##</code><code>##

$sql = "SELECT user_type FROM usersTable WHERE (username = ?)";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);
$sth->execute($user_name) or die("Could not execute!" . $dbh->errstr);