use strict;
use warnings;

use DBI;

my $dbname = 'testdb';
my $server = 'localhost';
my $user   = 'username';
my $pass   = 'password';

my $dbh = DBI->connect(
    "DBI:InterBase:" . "dbname=" . $dbname . ";host=" . $server .
        ";ib_dialect=3",
    $user, $pass,
    { AutoCommit => 1, RaiseError => 1, FetchHashKeyName => 'NAME_lc' }
);

my $sql4 = qq{
              SELECT
                 cant
               , vat
               , price
               , val
               , vat_val
               FROM v_testtable
};

eval {
    my $st = $dbh->prepare($sql4);

    $st->execute;

    while ( my $rez = $st->fetchrow_hashref() ) {
        print $rez->{cant} * $rez->{price} * $rez->{vat} /100,"\t";
        print "$rez->{vat_val}\n";
    }
};
if ($@) {
    warn "Transaction aborted because $@";
}

$dbh->disconnect();