Can I query MongoDB ObjectId by date?

Question

Popping Timestamps into ObjectIds covers queries based on dates embedded in the ObjectId in great detail.

Briefly in JavaScript code:

/* This function returns an ObjectId embedded with a given datetime */
/* Accepts both Date object and string input */

function objectIdWithTimestamp(timestamp) {
    /* Convert string date to Date object (otherwise assume timestamp is a date) */
    if (typeof(timestamp) == 'string') {
        timestamp = new Date(timestamp);
    }

    /* Convert date object to hex seconds since Unix epoch */
    var hexSeconds = Math.floor(timestamp/1000).toString(16);

    /* Create an ObjectId with that hex timestamp */
    var constructedObjectId = ObjectId(hexSeconds + "0000000000000000");

    return constructedObjectId
}


/* Find all documents created after midnight on May 25th, 1980 */
db.mycollection.find({ _id: { $gt: objectIdWithTimestamp('1980/05/25') } });

In pymongo, it can be done this way:

import datetime
from bson.objectid import ObjectId
mins = 15
gen_time = datetime.datetime.today() - datetime.timedelta(mins=mins) 
dummy_id = ObjectId.from_datetime(gen_time)
result = list(db.coll.find({"_id": {"$gte": dummy_id}}))

Using inbuilt function provided by mongodb drivers in in Node.js lets you query by any timestamp:

var timestamp = Date.now();
var objectId = ObjectID.createFromTime(timestamp / 1000);

Alternatively, to search for records before the current time, you can simply do:

var objectId = new ObjectID(); // or ObjectId in the mongo shell

Source: http://mongodb.github.io/node-mongodb-native/api-bson-generated/objectid.html

You can use $convert function to extract the date from ObjectId starting in 4.0 version.

Something like

$convert: { input: "$_id", to: "date" } 

You can query on date comparing between start and end time for date.

db.collectionname.find({
  "$expr":{
    "$and":[
      {"$gte":[{"$convert":{"input":"$_id","to":"date"}}, ISODate("2018-07-03T00:00:00.000Z")]},
      {"$lte":[{"$convert":{"input":"$_id","to":"date"}}, ISODate("2018-07-03T11:59:59.999Z")]}
    ]
  }
})

OR

You can use shorthand $toDate to achieve the same.

db.collectionname.find({
  "$expr":{
    "$and":[
      {"$gte":[{"$toDate":"$_id"}, ISODate("2018-07-03T00:00:00.000Z")]},
      {"$lte":[{"$toDate":"$_id"},ISODate("2018-07-03T11:59:59.999Z")]}
    ]
  }
})

how to find Find the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.find({
  _id: {
    $gt: ObjectId(Math.floor((new Date('2015/1/12'))/1000).toString(16) + "0000000000000000"), 
    $lt: ObjectId(Math.floor((new Date('2015/1/15'))/1000).toString(16) + "0000000000000000")
  }
}).pretty()

Count the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.count({
  _id: {
    $gt: ObjectId(Math.floor((new Date('2015/1/12'))/1000).toString(16) + "0000000000000000"), 
    $lt: ObjectId(Math.floor((new Date('2015/1/15'))/1000).toString(16) + "0000000000000000")
  }
})

Remove the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.remove({
  _id: {
    $gt: ObjectId(Math.floor((new Date('2015/1/12'))/1000).toString(16) + "0000000000000000"), 
    $lt: ObjectId(Math.floor((new Date('2015/1/15'))/1000).toString(16) + "0000000000000000")
  }
})

Since the first 4 bytes of an ObjectId represent a timestamp, to query your collection chronologically, simply order by id:

# oldest first; use pymongo.DESCENDING for most recent first
items = db.your_collection.find().sort("_id", pymongo.ASCENDING)

After you get the documents, you can get the ObjectId's generation time like so:

id = some_object_id
generation_time = id.generation_time