[{_id:"ddfdfdfdggfgfgsg",rate:"3323",quantity_packs:"343",shop_name:"Whole Foods",manufacturer_name:"Unilever"},{_id:"ddfdfdfsdsds",rate:"434",quantity_packs:"453",shop_name:"Carrefour",manufacturer_name:"Unilever"},{_id:"dfdfdgcvgfgfvvv",rate:"343",quantity_packs:"23",shop_name:"Target",manufacturer_name:"Beirsdorf"}]

db.collection.aggregate([{$match:{manufacturer_name:{$in:["Unilever"]}}},{$group:{_id:{"Shop Name":"$shop_name"},"annual_cost":{$sum:{$cond:[{$eq:["$manufacturer_name","Unilever"]},{$toInt:"$rate"},0]}},"annual_qty":{$sum:{"$toDouble":"$quantity_packs"}},}},{$project:{"Purchase_Cost":{$multiply:["$annual_cost","$annual_qty"]},}}])