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db.collection.aggregate([{$project:{"Data.children":{$objectToArray:"$Data.children"}}},{$unwind:"$Data.children"},{$group:{_id:"$Data.children.k",name:{$last:"$Data.children.v.name"},cost:{$sum:"$Data.children.v.cost"},revenue:{$sum:"$Data.children.v.revenue"},grandchildren:{$push:"$Data.children.v.grandchildren"}}},{$unwind:"$grandchildren"},{$addFields:{grandchildren:{$objectToArray:"$grandchildren"}}},{$unwind:"$grandchildren"},{$group:{_id:{ck:"$_id",gck:"$grandchildren.k"},cost:{$first:"$cost"},revenue:{$first:"$revenue"},name:{$first:"$name"},grandchildren_cost:{$sum:"$grandchildren.v.cost"},grandchildren_revenue:{$sum:"$grandchildren.v.revenue"}}},{$group:{_id:"$_id.ck",cost:{$first:"$cost"},revenue:{$first:"$revenue"},name:{$last:"$name"},grandchildren:{$push:{k:"$_id.gck",v:{cost:"$grandchildren_cost",revenue:"$grandchildren_revenue"}}}}},{$group:{_id:null,children:{$push:{k:"$_id",v:{name:"$name",cost:"$cost",revenue:"$revenue",grandchildren:{$arrayToObject:"$grandchildren"}}}}}},{$project:{_id:0,"Data.children":{$arrayToObject:"$children"}}}])