#!/usr/bin/perl -w
use strict;
use DBI;
my $dbh=DBI->connect("dbi:CSV(RaiseError=1):csv_eol=\n");

sub MyCalc { $_[3] * 2 }
$dbh->do("CREATE FUNCTION MyCalc");

my $sth = $dbh->prepare(q{  SELECT sales,MyCalc(sales) FROM Test });
$sth->execute;
$sth->dump_results();
__END__
#
# given sales values of 2 and 5, this script outputs
#
#    2,4
#    5,10