aggregate([{
        "$match": {
            "timestamp": {
                "$gte": ISODate("2018-12-18T12:23:48Z"),
                "$lte": ISODate("2018-12-19T12:23:48Z")
            },
            "equipment_id": NumberLong(168)
        }
    }, {
        "$group": {
            "_id": "$timestamp",
            "__agg0" : { "$sum" : "$my_decimal_value" }
        }
    }, {
        "$project": {
            "timestamp": "$_id",
            "sqrt_calc": { "$sqrt" : ["$__agg0"] }
            "_id": 0
        }
    }, {
        "$sort": {
            "timestamp": 1
        }
    }
])