MongoDB greater than numberLong issue

Question

I am trying to get all documents in a collection in which the date, stored as this:

{
  "_id": {
    "$oid": "5c500ff8df157e051961cfab"
  },
  "date": {
    "$date": {
      "$numberLong": "1548750839931"
    }
  },
  "when": "2019-1-29T8:33Z",
  "score": 20
}

... is greater than this: 1546300800000

I have 2 records in my collection, but I get none in return?

Here is my query:

{"date":{"$gt": 1546300800000}}

I guess that is has something to do with the date is stored as string, but can it be done?

Hoping for help and many thanks in advance :-)

Answer 1

Your date is saved as Date type and you are using timestamp to find the documents.

So, You can first convert date to timestamp using $toLong aggregation operator and then use $gt operator

If you are using mongodb 4.0

db.collection.find({
  "$expr": {
    "$gt": [{ "$toLong": "$date" }, 1546300800000]
  }
})

If you are using mongodb 3.6

db.collection.find({
  "$expr": {
    "$gt": [
      { "$subtract": ["$date", new Date("1970-01-01")] },
      1546300800000
    ]
  }
})

or you can simply convert your timestamp to type date

db.collection.find({
  "date": { "$gt": new Date(1546300800000) }
})