Check that Field Exists with MongoDB

You can use $ne (for “not equal”)

db.collection.find({ "fieldToCheck": { $exists: true, $ne: null } })

Try to use this:

{
"_id":"1234"
"open":"Yes"
"things":{
            "paper":1234
            "bottle":"Available"
            "bottle_count":40
          }
}

You want to know if the bottle field is present of not ?

Answer:

db.products.find({"things.bottle":{"$exists":true}})

Just try to do it:

db.getCollection('collectionName').findOne({"fieldName" : {$ne: null}})