Database
[{"ParentID":1,"Datatype":"pizza","Date":ISODate("2020-01-01T17:01:23.293Z")},{"ParentID":1,"Datatype":"pizza","Date":ISODate("2020-01-02T17:01:23.293Z")},{"ParentID":2,"Datatype":"pizza","Date":ISODate("2020-01-01T17:01:23.293Z")},{"ParentID":2,"Datatype":"pizza","Date":ISODate("2020-01-02T17:01:23.293Z")},{"ParentID":1,"Datatype":"Burger","Date":ISODate("2020-01-01T17:01:23.293Z")}]
Query
db.collection.aggregate([{$group:{_id:{parentName:"$ParentID",maintainancename:"$Datatype"},"Date":{$max:"$Date"}}}])