[{"bus":"EXAMP","city":"Kanpur","AccountName":"Examp Transport Service","agencyName":"BBS","depotName":"RAYAPUR HUBLI","CashCollection":8,"Collection":30,"IssueTicket":5,"PassengerCount":4,"TicketCount":4},{"bus":"EXAMP","city":"Kanpur","AccountName":"Examp Transport Service","agencyName":"BBS","depotName":"RAYAPUR HUBLI","CashCollection":10,"Collection":20,"IssueTicket":7,"PassengerCount":5,"TicketCount":4}]

db.collection.aggregate([{"$match":{bus:"EXAMP"}},{"$facet":{"result":[{"$group":{"_id":"$bus","bus":{"$first":"$bus"},"city":{"$first":"$city"},"AccountName":{"$first":"$AccountName"},"agencyName":{"$first":"$agencyName"},"depotName":{"$first":"$depotName"}}}],aggregate:[{"$group":{"_id":null,"totalCollection":{$sum:"$Collection"},"IssueTicket":{$sum:"$IssueTicket"},"PassengerCount":{$sum:"$PassengerCount"},"TicketCount":{$sum:"$TicketCount"}}}]}},{$set:{aggregate:{"$ifNull":[{"$arrayElemAt":["$aggregate",0]},null]}}}])