File: Data.xml
File: Query.xquery
let $allcars := doc("Data.xml")//car
for $d in distinct-values($allcars/@model)
for $n in distinct-values($allcars/@num)
let $cars := $allcars[@model = $d and @num = $n]
where sum($cars/@quantity) > 1
order by count($cars)
return if (exists($cars))
then
else ()
Output: