{ let $end_dates := doc("items.xml")//item_tuple/end_date for $m in distinct-values(for $e in $end_dates return month-from-date($e)) let $item := doc("items.xml") //item_tuple[year-from-date(end_date) = 1999 and month-from-date(end_date) = $m] order by $m return { $m } { count($item) } }