MongoDB query to get specific month|year (not date)?

To get specific month or year values from MongoDB date fields, use the aggregation framework with $month and $year operators. These operators extract the numeric month (1-12) and year values from date fields.

Syntax

db.collection.aggregate([
    { $project: { field: 1, dateField: { $month: "$dateField" } } },
    { $match: { dateField: monthNumber } }
]);

Sample Data

db.specificMonthDemo.insertMany([
    { "StudentName": "Larry", "StudentDateOfBirth": new ISODate("1995-01-12") },
    { "StudentName": "Chris", "StudentDateOfBirth": new ISODate("1999-12-31") },
    { "StudentName": "David", "StudentDateOfBirth": new ISODate("2000-06-01") }
]);

{
    "acknowledged": true,
    "insertedIds": [ ObjectId("..."), ObjectId("..."), ObjectId("...") ]
}

Display all documents to verify the data ?

db.specificMonthDemo.find().pretty();

{
    "_id": ObjectId("5cb9a9ca8f1d1b97daf71819"),
    "StudentName": "Larry",
    "StudentDateOfBirth": ISODate("1995-01-12T00:00:00Z")
}
{
    "_id": ObjectId("5cb9a9db8f1d1b97daf7181a"),
    "StudentName": "Chris",
    "StudentDateOfBirth": ISODate("1999-12-31T00:00:00Z")
}
{
    "_id": ObjectId("5cb9a9ee8f1d1b97daf7181b"),
    "StudentName": "David",
    "StudentDateOfBirth": ISODate("2000-06-01T00:00:00Z")
}

Method 1: Get Specific Month

Find students born in January (month 1) ?

db.specificMonthDemo.aggregate([
    { $project: { 
        StudentName: 1, 
        StudentDateOfBirth: { $month: "$StudentDateOfBirth" } 
    } },
    { $match: { StudentDateOfBirth: 1 } }
]);

{
    "_id": ObjectId("5cb9a9ca8f1d1b97daf71819"),
    "StudentName": "Larry",
    "StudentDateOfBirth": 1
}

Method 2: Get Specific Year

Find students born in 1999 ?

db.specificMonthDemo.aggregate([
    { $project: { 
        StudentName: 1, 
        birthYear: { $year: "$StudentDateOfBirth" } 
    } },
    { $match: { birthYear: 1999 } }
]);

{
    "_id": ObjectId("5cb9a9db8f1d1b97daf7181a"),
    "StudentName": "Chris",
    "birthYear": 1999
}

Method 3: Extract Both Month and Year

db.specificMonthDemo.aggregate([
    { $project: { 
        StudentName: 1,
        birthMonth: { $month: "$StudentDateOfBirth" },
        birthYear: { $year: "$StudentDateOfBirth" }
    } }
]);

{
    "_id": ObjectId("5cb9a9ca8f1d1b97daf71819"),
    "StudentName": "Larry",
    "birthMonth": 1,
    "birthYear": 1995
}
{
    "_id": ObjectId("5cb9a9db8f1d1b97daf7181a"),
    "StudentName": "Chris",
    "birthMonth": 12,
    "birthYear": 1999
}
{
    "_id": ObjectId("5cb9a9ee8f1d1b97daf7181b"),
    "StudentName": "David",
    "birthMonth": 6,
    "birthYear": 2000
}

Conclusion

Use $month and $year operators within aggregation pipelines to extract specific date components. The $project stage extracts the values, and $match filters documents based on the extracted month or year numbers.