[{"product":"p1","salesdate":"2020-02-01","amount":100},{"product":"p2","salesdate":"2020-02-04","amount":200},]

db.collection.aggregate([{$match:{"salesdate":{$gte:"2020-02-01",$lte:"2020-02-05"}}},{$project:{"_id":0,"amount":{$sum:"$amount"},"salesdate":1}}])