$dbh=$db->prepare("SELECT -balance FROM Table1 
                   WHERE  username='$authuser' 
                          and balance < '-.01'");
$dbh->execute();
($balance_due) = $dbh->fetchrow_array();

##</code><code>##

$dbh=$db->prepare("SELECT -balance FROM Table1 
                   WHERE  username='$authuser' 
                          and balance < '-.01'");
$dbh->execute();
($tmp) = $dbh->fetchrow_array();
$balance_due = 0 - $tmp;

##</code><code>##

$dbh=$db->prepare("SELECT -balance FROM Table1 
                   WHERE  username='$authuser' 
                          and balance < '-.01'");
$dbh->execute();
($tmp) = $dbh->fetchrow_array();
$balance_due = substr $tmp, 1;