Database
[{"meter_id":"1001","date":new Date(1509474600000),"parameter_name":"hvac","voltage":{"unit":"V"},"current":{"unit":"AMP"},"powerFactor":{"unit":"phi"},"angle":{"unit":"degree"},"activePower":{"unit":"kwh"},"reactivePower":{"unit":"kwh"},"apparentPower":{"unit":"kwh"},"frequency":{"unit":"hz"},"thd":{"unit":"percentage"},"energy":{"Energy":5.7},"power":{"unit":"watt"}}]
Query
db.collection.aggregate([{$match:{date:{$gte:ISODate("2016-12-12")}}},{$group:{_id:"$meter_id",total:{$sum:1},totalEnergy:{$sum:"$energy.Energy"}}}])