[{app:"app1",status:"success",count:5},{app:"app1",status:"fail",count:4},{app:"app1",status:"blocked",count:3},{app:"app1",status:"transferred",count:6}]

db.collection.aggregate([{"$group":{"_id":{app:"$app",status:{"$switch":{"branches":[{"case":{$eq:["$status","success"]},"then":"success"}],"default":"failed"}}},"count":{"$sum":"$count"}}}])