JIYIK CN >

This MongoDB tutorial article will explain Date()the methods. This article introduces different ways to query using dates.

Date() Method in MongoDB

Date()The method returns the date as a string or a Date object.

1. In the MongoDB shell or mongosh, the Date() method returns the current date as a string.
2. The new Date() function returns a Date object containing the current date. The ISODate helper is wrapped by mongosh around the Date object. ISODate is in UTC (Coordinated Universal Time).

You can use the new Date()function or ISODate()method to define a specific date by providing an ISO-8601 date string with a year between "0" and "9999". These functions accept the following formats.

1. An ISODate with the supplied date is returned by new Date("").
2. new Date("") specifies a DateTime in the client's local time zone and returns an ISODate and a DateTime in UTC.
3. new Date("") takes a DateTime in UTC format and returns an ISODate with the DateTime in UTC format.
4. new Date(integer>) Returns an ISODate instance where the DateTime specifies the number of milliseconds since the UNIX epoch (January 1, 1970).

Date() Method Behavior

Date objects are stored internally as a signed 64-bit integer representing the number of milliseconds since the Unix epoch (January 1, 1970). Not all database procedures and drivers support the full 64-bit range.

Dates with years between 0 and 9999 can be handled safely.

Using the Date() method in MongoDB queries

_idIf a document with date equal to 1 does not exist in the products collection , the following code adds a document and sets the field dateAdded to the current date.

Code:

db.products.updateOne(
   { _id: 1 },
   {
     $set: { item: "apple" },
     $setOnInsert: { dateAdded: new Date() }
   },
   { upsert: true }
)

Use Date()the method to return a date as a string, as the following example shows:

var myDateString = Date();

mongosh uses the ISODate helper to wrap objects of type Date. However, the objects are still of type Date.

The following example uses new Date()to return a Date object with the specified UTC date-time.

var myDate = new Date("2016-05-18T16:00:00Z");

Sorting by date in MongoDB

This problem is solved using the sort() function and the $sort aggregation in MongoDB. You can use this tool to sort the data in ascending or descending order.

Code example:

db.posts.find().pretty()
{
    "_id" : 1,
    "title" : "MongoDB",
    "body" : "Hi there",
    "date" : "2021-01-01T00:00:00.000Z",
        "Country" : "United Kingdom"
}
{
    "_id" : 2,
    "title" : "MySQL",
    "body" : "Hello",
    "date" : ISODate("2020-01-01T00:00:00Z"),
        "Country" : "United States of America"
}
{
    "_id" : 3,
    "title" : "SQL",
    "body" : "World",
    "date" : ISODate("2021-01-01T00:00:00Z"),
        "Country" : "New Zealand"
}

Some data is added to the posts collection, and the date field is used to sort them in ascending order, with older dates first.

Code example:

db.posts.find().sort({ date: 1 }).pretty()
{
    "_id" : 1,
    "title" : "MongoDB",
    "body" : "Hi there",
    "date" : "2021-01-01T00:00:00.000Z",
        "Country" : "United Kingdom"
}
{
    "_id" : 2,
    "title" : "MySQL",
    "body" : "Hello",
    "date" : ISODate("2020-01-01T00:00:00Z"),
        "Country" : "United States of America"
}
{
    "_id" : 3,
    "title" : "SQL",
    "body" : "World",
    "date" : ISODate("2021-01-01T00:00:00Z"),
        "Country" : "New Zealand"
}

After sorting, notice it because the first document has a date string instead of a date object.

The date string appears first, even though the date in document 2 was initialized later.

Sorting by date not working in MongoDB

There could be many reasons why MongoDB is not working, but you must remember some procedures for sorting operations by date in MongoDB.

1. Always remember that with help you are storing data in collections.
2. There are two ways to store date fields in a document.
3. The Date() string and ISODate() data types are used to store dates in documents.
4. When you sort a date field using the sort() method, check which data type you are using.

Code example:

db.document.insertOne({ "productId" : 1001, "productDeliveryDateTime": new Date() });
{
        "acknowledged" : true,
        "insertedId" : ObjectId("611c9e39e1fdc428cf238802")
}

Add date using Date() string, collection name is document. You can insert date in document in the same way using ISODate().

Querying working dates using ISODate() in MongoDB

Date query using ISODate in MongoDB using $gte operator and ISODate() Let us make a collection using this document to understand the concept better.

Following is the query to construct a collection using documents.

Query:

> db.dateDemo.insertOne({"StudentName":"John","StudentAge":26,"AdmissionDate":new ISODate("2013-06-07")});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c8a65799064dcd4a68b70ea")
}

find()The function displays all documents in a collection.

ask:

db.dateDemo.find().pretty();

Output:

This is a date query using ISODate() in MongoDB.

Query:

> db.dateDemo.find({"AdmissionDate":{"$gte": ISODate("2013-06-07T00:00:00Z")}}).pretty();

Output: