[{"_id":123,"weapons":[{"name":"Sword","durability":100},{"name":"Shield","durability":50}]},{"_id":456,"weapons":[{"name":"Sword","durability":100},{"name":"Shield","durability":0}]},{"_id":789,"weapons":[{"name":"Sword","durability":50},{"name":"Hammer","durability":50}]}]

db.collection.find({"weapons.name":{"$nin":["Hammer"]}})