Database
[{_id:"1",Name:"",CarData:{carId:"1",ownerName:"1",ownerPhone:"1",AdditionalInfo:{RefNr:"",validDoc:true}}},{_id:"2",Name:"",CarData:{}},{_id:"3",Name:"",CarData:{carId:"1",ownerName:"",ownerPhone:"1",AdditionalInfo:{RefNr:"",validDoc:true}}}]
Query
db.collection.find({"CarData.ownerName":{"$ne":""},"CarData.AdditionalInfo.validDoc":true})