my $dbh = DBI->connect(q{DBI:CSV:});
$dbh->{'csv_tables'}->{'mytable'} = {
    'file'      => 'mytable.csv',
    'sep_char'  => "\t"
    'col_names' => ["col_a", "col_b", "col_c"]
};

my $sth = $dbh->prepare("SELECT m.col_a, m.col_c FROM mytable m");
$sth->execute;

my @rows;
while (my $row = $sth->fetchrow_hashref) {
    push @rows, $row;
}