Database
[{"total":48.0,"status":"CO"},{"total":11.0,"status":"CA"},{"total":15916.0,"status":"PE"}]
Query
db.collection.aggregate([{$group:{_id:null,total:{"$sum":{"$switch":{"branches":[{"case":{$eq:["$status","PE"]},"then":"$total"},{"case":{$eq:["$status","CO"]},"then":{$subtract:[0,"$total"]}},{"case":{$eq:["$status","CA"]},"then":{$subtract:[0,"$total"]}}],default:0}}}}}])