my $type_i_want = $dbh->type_info( [ SQL_whatever ] );
# 
# ...later...
#
$sth->execute(@parameters);
my @types = $sth->{TYPE};
my $row = $sth->fetch();
for (my $i = 0; $i < $sth->{NUM_OF_FIELDS}; $i++)
{
    if ($types[$i] eq $type_i_want)
    {
        printf "0x%x", $row[$i];
    }
    else
    {
        printf "%s", $row[$i];
    }
}