sub {

my $this_cat_id = $_[0];
my $this_father_id = $_[1];

if (!$this_cat_id || !$this_father_id) { return; }

my $tbl = $DB->table('Category');
$tbl->select_options("ORDER BY Name ASC");
my $sth = $tbl->select( { FatherID => $this_father_id } );

my $prev = {};
my $prev_cat = {};
my $next_cat = {};
my $now_find_next = 0;
while (my $hit = $sth->fetchrow_hashref) {


if ($hit->{ID} == $this_cat_id) {
$prev_cat = $prev;
$now_find_next = 1;
}

if ($now_find_next == 1) {
$now_find_next++;
} elsif ($now_find_next == 2) {
$next_cat = $hit;
last;
}

$prev = $hit;

}

if ($prev_cat->{ID}) {
$prev_cat->{URL} = $CFG->{build_root_url} . "/". $tbl->as_url( $prev_cat->{Full_Name} ) . "/";
}
if ($next_cat->{ID}) {
$next_cat->{URL} = $CFG->{build_root_url} . "/". $tbl->as_url( $next_cat->{Full_Name} ) . "/";
}

return { 'prev_cat' => $prev_cat, 'next_cat' => $next_cat }

}

<%get_cat_prev_and_next($ID,$FatherID)%>
<%if $prev_cat.ID%>
Prev Category "<a href="<%prev_cat.URL%>"><%prev_cat.Name%></a>"
<%endif%>

<%if $next_cat.ID%>
Next Category "<a href="<%next_cat.URL%>"><%next_cat.Name%></a>"
<%endif%>