[{"id":"101","userName":"John","date":"2023-03-20"},{"id":"102","userName":"Deo","date":"2023-01-11"},{"id":"102","userName":"Yeh","date":"2023-1-11"},{"id":"103","userName":"Swim","date":"2021-11-14"},{"id":"104","userName":"Piter","date":"2021-06-21"},{"id":"105","userName":"yogo","date":"2021-10-05"}]

db.collection.aggregate([{$group:{_id:{$substr:["$date",0,4]},users:{$push:{id:"$id",userName:"$userName",date:"$date"}}}}])