Query for a field in an object in array with Mongo?

This is an old question, but a simpler way to perform this query is to use dot notation:

db.collection.find({'field1.one': 1})

I suppose what you need is:

db.collection.find( { field1: { $elemMatch: { one: 1 } } } );

http://docs.mongodb.org/manual/reference/operator/elemMatch/#op._S_elemMatch