Greetings celliott,

I'm not sure I entirely follow what you're wanting to do, but if I'm understanding you correctly, this might help:

my $data = $dbh->selectall_arrayref(
    'SELECT ID, NUM FROM INDEX WHERE ID LIKE F% OR ID LIKE G%',
    { Columns => {} }
);

my %index;
foreach (@{ $data }) {
    if ($_->{'ID'} eq 'G') {
        $index{$_->{'NUM'}} = -1;
    } else {
        $index{$_->{'NUM'}} = 1 if (not exists $index{$_->{'NUM'}});
    }
}

my @index;
foreach (keys %index) {
    push @index, 'F' . $_ if ($index{$_} == 1);
}

print join("\n", @index), "\n";
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Instead of dealing with all the bind_param and bind_column stuff, I just selectall_arrayref into a reference, then foreach through that to populate %index. It seems to work for me, but I don't like it. It requires looping twice, which just feels like it would be slow. Plus, there's got to be a way to do this with a couple maps, but apparently I'm not smart enough to figure that out today.