MongoDB query to find a value from JSON like data?

To find a value from JSON-like data in MongoDB, use the find() method along with dot notation to access nested fields within embedded documents and arrays.

Syntax

db.collection.find({"field.nestedField": "value"})

Sample Data

db.findValueFromJsonDemo.insertOne({
    "UserDetails": [{
        "_id": ObjectId(),
        "UserName": "Carol",
        "UserMessage": "Hi"
    }],
    "UserFriendsName": ["John", "Sam"]
});

{
    "acknowledged": true,
    "insertedId": ObjectId("5cdf8a4cbf3115999ed511fd")
}

Display All Documents

db.findValueFromJsonDemo.find().pretty();

{
    "_id": ObjectId("5cdf8a4cbf3115999ed511fd"),
    "UserDetails": [
        {
            "_id": ObjectId("5cdf8a4cbf3115999ed511fc"),
            "UserName": "Carol",
            "UserMessage": "Hi"
        }
    ],
    "UserFriendsName": [
        "John",
        "Sam"
    ]
}

Find Value in Nested Field

To find documents where UserMessage equals "Hi" within the UserDetails array ?

db.findValueFromJsonDemo.find({"UserDetails.UserMessage": "Hi"});

{
    "_id": ObjectId("5cdf8a4cbf3115999ed511fd"),
    "UserDetails": [
        {
            "_id": ObjectId("5cdf8a4cbf3115999ed511fc"),
            "UserName": "Carol",
            "UserMessage": "Hi"
        }
    ],
    "UserFriendsName": [
        "John",
        "Sam"
    ]
}

Key Points

• Use dot notation to access nested fields: "parentField.childField"
• MongoDB automatically searches within arrays when using dot notation
• The query returns the entire document when a match is found

Conclusion

Use dot notation with the find() method to query nested values in JSON-like MongoDB documents. This approach works seamlessly with embedded documents and arrays.