FOR u IN users
  LET recommendations = ( 
    FOR r IN recommendations
      FILTER u.id == r.userId
      SORT u.rank DESC
      LIMIT 10
      RETURN r
  )
  RETURN { "user" : u, "recommendations" : recommendations }
   
  
FOR u IN users
  COLLECT city = u.city INTO g
  RETURN { "city" : city, "numUsers" : LENGTH(g), "maxRating": MAX(
    FOR r IN g 
      RETURN r.user.rating
  ) }