How to use $dayOfYear aggregation with epoch timestamps

Asked Jan 29 '18 at 13:53

Active Jan 29 '18 at 13:58

Viewed 235 times

I have my documents in this format:

{
    "_id": 1517209200000,       
    "timestamp": 1517209200000,
    "current": 236078,
}

Timestamp is an epoch representation of a date, with about 100 documents inserted per day. It's stored as a number.

I'm trying to figure out how to print last 30 days with average $current as well as min and max for each day.

I found the $dayOfYear aggregation however I am not sure how to apply it to my epoch timestamps. (https://docs.mongodb.com/manual/reference/operator/aggregation/dayOfYear/)

Could anyone share their knowledge if they know the answer?

Thank you

EDIT: my first attempt that returns an error: "errmsg" : "can't convert from BSON type double to Date",

db.cable23.aggregate([ { $match: {'direction': 0} },{$group : {'_id': {'$year': "$timestamp"}}}])

edited Jan 29 '18 at 13:58

asked Jan 29 '18 at 13:53

LucasSeveryn

Timestamp you are storing as a `Date` type or any other? – Saikat Chakrabortty Jan 29 '18 at 13:58
storing as a number – LucasSeveryn Jan 29 '18 at 13:58
2

Try `db.cable23.aggregate([ { $match: {'direction': 0} },{$group : {'_id': {'$year': { "$add": [ new Date(0), "$timestamp" ] }}}}])` – s7vr Jan 29 '18 at 14:00
can you try by making it `Date` Type? most probably my guess is, as timestamp is a number type. Mongo is unable to make query with that, while `$year` only deals with `Date` type things. – Saikat Chakrabortty Jan 29 '18 at 14:00
1

you mean re-fill whole database with a date type? The question is on how to avoid it. – LucasSeveryn Jan 29 '18 at 14:01

0 Answers0