Hi I have a script that draws two queries from a PostgreSQL database full of bus timetable data and then compares them for similar results in one column. The advice that I was given before was to use one ash and one array to fetermine which values are the same in either query. This ocde looks something like this: 
my %ids;

$origsql = qq{ SELECT route_number, stop_reference, depart_time FROM r
+outes WHERE distance < 200...........}; #all SQL code not included he
+re
$sth = $dbh->prepare( $origsql );
$sth->execute();
$sth->bind_columns( undef, \$orig_service_id, \$orig_stop, $depart_ori
+g);
while ($sth->fetch())
{
push(@orig_service_ids, $orig_service_id);
}
for my $id (@orig_service_ids) {
    $ids{$id} = 1;
}

# ...


$destsql = qq{ SELECT route_number, stop_reference, depart_time FROM r
+outes WHERE distance < 200...........}; #all SQL code not included he
+re
$sth = $dbh->prepare( $destsql );
$sth->execute();
$sth->bind_columns( undef, \$dest_service_id, \$dest_stop, $depart_des
+t);
while ($sth->fetch())
{
push(@dest_service_ids, $dest_service_id);
}
for my $id (@dest_service_ids) {
    if (exists $ids{$id}) {
        print "ID $id exists in both origin and destination set\n";
    }
}

[download]
Now this works excellently as it tells me which service from my origin matches in my destination. However how can I also gain access to the associated data with each row in the query? For example, if I find that both queries have the same service, how can I then find the associate stops from the query relating to that service for each my origin and my destination? Do I have to make an array for each other variable in the queries too or a hash for each? Im not really an expert on hashes so any help and advice would be more than welcome. Thanks

In reply to Keeping associated data after entering into a hash by Harch84

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