gistfile1.txt

{"rp":
  {"AdSpot": [
    {"1": {"mt": {"im": {"va": 141}, "ck": {"va": 13}}}},
    {"2": {"mt": {"im": {"va": 237}, "ck": {"va": 12}}}},
    {"3": {"mt": {"im": {"va": 671}, "ck": {"va": 21}}}}]
  },
 "_id": ObjectID("a")
}

{"rp":
  {"AdSpot": [
    {"2": {"mt": {}},
    {"4": {"mt": {"im": {"va": 123}, "ck": {"va": 13}}}},
    {"5": {"mt": {"im": {"va": 999}, "ck": {"va": 13}}}}]
  },
 "_id": ObjectID("b")
}

{"rp":
  {"AdSpot": [
    {"4": {"mt": {"im": {"va": 0}}}},
    {"5": {"mt": {"im": {"va": 13}, "ck": {"va": 11}}}},
    {"6": {"mt": {"im": {"va": 2}, "ck": {"va": 9}}}}]
  },
 "_id": ObjectID("c")
}

# I want to find documents a and b, given [1, 2]. a matches because rp.AdSpot has keys of both 1 and 2.
# Document b matches because 2 is one of the keys of rp.AdSpot.

db.collection.find({...})