[{"_id":ObjectId("5d6db92e8e935c407f00f39c"),"id":"1","email":"admin@test.com","orgs":[{"org_id":"1","org_name":"Lenovo","role":"tenantadmin","primary_locale":null,"name":"admin"}]},{"_id":ObjectId("5d6db92e8e935c407f00f39d"),"id":"1","email":"admin@test.com","orgs":[{"org_id":"1","org_name":"Lenovo","role":"admin","primary_locale":null,"name":"admin"}]}]

db.collection.aggregate([{"$unwind":"$orgs"},{"$group":{"_id":{$cond:[{$eq:["$orgs.role","admin"]},"$orgs.role","other"]},"count":{"$sum":1}}}])