mongodb find document based on 2 fields code example

Example 1: mongodb find documents where two fields are equal

db.myCollection.find( { $where: "this.a1.a != this.a2.a" } )

Example 2: mongodb match multiple fields

$match:
{
	$and: [
    {'ExtraFields.value': {$in: ["A52A2A"]}}, 
    {'ExtraFields.fieldID': ObjectId("5535627631efa0843554b0ea")}
    ]
}