MongoDB query to remove subdocument from document?

To remove a subdocument from a document in MongoDB, use the $pull operator along with update(). The $pull operator removes all array elements that match a specified condition.

Syntax

db.collection.update(
    { "matchField": "value" },
    { $pull: { "arrayField": { "field": "condition" } } }
);

Create Sample Data

db.demo538.insertOne({
    id: 101,
    "details": {
        anotherDetails: [
            {
                "Name": "Chris",
                Age: 21
            },
            {
                "Name": "David",
                Age: 23
            },
            {
                "Name": "Bob",
                Age: 20
            }
        ]
    }
});

{
    "acknowledged": true,
    "insertedId": ObjectId("5e8c8f0aef4dcbee04fbbc08")
}

Display Original Document

db.demo538.find();

{
    "_id": ObjectId("5e8c8f0aef4dcbee04fbbc08"),
    "id": 101,
    "details": {
        "anotherDetails": [
            { "Name": "Chris", "Age": 21 },
            { "Name": "David", "Age": 23 },
            { "Name": "Bob", "Age": 20 }
        ]
    }
}

Remove Subdocument

Remove the subdocument where Age is 23 ?

db.demo538.update(
    { id: 101 },
    { $pull: { "details.anotherDetails": { "Age": 23 } } }
);

WriteResult({ "nMatched": 1, "nUpserted": 0, "nModified": 1 })

Verify Result

db.demo538.find();

{
    "_id": ObjectId("5e8c8f0aef4dcbee04fbbc08"),
    "id": 101,
    "details": {
        "anotherDetails": [
            { "Name": "Chris", "Age": 21 },
            { "Name": "Bob", "Age": 20 }
        ]
    }
}

Conclusion

Use $pull with update() to remove subdocuments from arrays. The operator removes all elements matching the specified condition, making it effective for cleaning nested array data.