MongoDB/PyMongo: Querying multiple criteria - unexpected results

Question

I have a collection where some of the objects feature an key foo. I now try to query for all objects that indeed have this key but not with the specific value <

Answer 1

You can use $and to join multiple conditions:

collection.find({"$and": [{"foo": {'$ne': 'bar'}}, 
                          {"foo": {'$exists': True}}]})

Answer 2

No necessary to use $and, it also works

db.collection.find({"foo":{"$ne":"bar", "$exists":true}})