[{firstname:"user1",lastname:"user",gender:"male",email:"user@users.com",houses:{"New York":["house1","house2"],"Florida":["house1","house2"]}},{firstname:"user2",lastname:"user",gender:"female",email:"user2@users.com",houses:{"Florida":["house1"],"Texas":["house1"]}}]

db.collection.aggregate([{$match:{"houses.Texas":{$exists:true}}}])