You are looking at a very old, but free version of the course. If you are interesed the most recent version, check it out on the Perl Maven site.

13.6. SELECT, prepare with placeholders

Example 13-4. examples/dbi/

use strict;
use warnings;

use DBI;

my $dbfile = "sample.db";

my $dbh = DBI->connect("dbi:SQLite:dbname=$dbfile");

my $sth = $dbh->prepare('SELECT fname, lname FROM users WHERE id <= ?');

while (my @row = $sth->fetchrow_array()) {
    print "$row[0] $row[1]\n";

If you are interested in on-site trainings by the author, please contact me directly.