Aldeed tabular selector comparing two fields

help
1

Hi Guys,

Im using Aldeed Tabular and its selector. I wonder how to compare between two fields just like this in mongoD=> db.T.find( { $where : "this.Grade1 > this.Grade2" } );

well i can use this selector to compare fields with some values, for example
nilaiActual:{'$gt':0}, but how can I compare between two fields just like the example above??

Thank you