[{stationName:"test-1",systemName:"test",commodities:[{name:"name",buyPrice:1,sellPrice:2,stock:3,demand:4}]},{stationName:"test-2",systemName:"test",commodities:[{name:"name",buyPrice:4,sellPrice:5,stock:6,demand:7}]},{stationName:"test-3",systemName:"test",commodities:[{name:"name",buyPrice:8,sellPrice:9,stock:10,demand:11}]},]

db.collection.aggregate([{$project:{stationName:true,systemName:true,maxBuyPrice:{$max:"$commodities.buyPrice"},maxSellPrice:{$max:"$commodities.sellPrice"},}}])