sub ListCategories {

    my (%cat,
        $sql_query,
	$already_run,
	$parent_cat_id,
	$indent,
	$all_cats
	);

    $indent = $_[0];
    $parent_cat_id = $_[1];
    $already_run = $_[2];

    print $query->header if ($already_run ne 'y');

    if ($parent_cat_id >= 0) {

	if ($parent_cat_id == 0) {
            $all_cats = $dbh->selectall_arrayref("SELECT category_id,name FROM $sql{categories} WHERE parent IS NULL");
        }

        elsif ($parent_cat_id > 0) {
            $all_cats = $dbh->selectall_arrayref("SELECT category_id,name FROM $sql{categories} WHERE parent=$parent_cat_id");
            $indent .= "     ";		
        }

        foreach my $current_cat (sort { $a->[1] cmp $b->[1] } @{$all_cats}) {
            ($cat{id}, $cat{name}) = @$current_cat;
            print "$indent $cat{name} ($cat{id})<br>";
            &ListCategories($indent, $cat{id}, 'y');
        }
    }
}