How to search for string or number in a field with MongoDB?

To search for string or number values in a field with MongoDB, use the $in operator with an array containing both the string and numeric versions of the value you want to match.

Syntax

db.collection.find({
    "fieldName": { $in: ["stringValue", numericValue] }
});

Sample Data

Let us create a collection with documents containing both string and numeric values ?

db.searchForStringOrNumberDemo.insertMany([
    {
        "StudentName": "Larry",
        "StudentDetails": {
            "StudentMarks": {
                "StudentMongoDBMarks": [44]
            }
        }
    },
    {
        "StudentName": "Larry",
        "StudentDetails": {
            "StudentMarks": {
                "StudentMongoDBMarks": ["44"]
            }
        }
    }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5ce2407c36e8b255a5eee944"),
        ObjectId("5ce240f036e8b255a5eee945")
    ]
}

View Sample Data

db.searchForStringOrNumberDemo.find().pretty();

{
    "_id": ObjectId("5ce2407c36e8b255a5eee944"),
    "StudentName": "Larry",
    "StudentDetails": {
        "StudentMarks": {
            "StudentMongoDBMarks": [44]
        }
    }
}
{
    "_id": ObjectId("5ce240f036e8b255a5eee945"),
    "StudentName": "Larry",
    "StudentDetails": {
        "StudentMarks": {
            "StudentMongoDBMarks": ["44"]
        }
    }
}

Search for String or Number

Use $in with both string and numeric values to match either data type ?

db.searchForStringOrNumberDemo.find({
    "StudentDetails.StudentMarks.StudentMongoDBMarks": { 
        $in: ["44", 44] 
    }
});

{
    "_id": ObjectId("5ce2407c36e8b255a5eee944"),
    "StudentName": "Larry",
    "StudentDetails": {
        "StudentMarks": {
            "StudentMongoDBMarks": [44]
        }
    }
}
{
    "_id": ObjectId("5ce240f036e8b255a5eee945"),
    "StudentName": "Larry",
    "StudentDetails": {
        "StudentMarks": {
            "StudentMongoDBMarks": ["44"]
        }
    }
}

Key Points

• The $in operator matches any value in the provided array
• Include both string and numeric versions to handle type variations
• Works with nested fields using dot notation

Conclusion

Use the $in operator with an array containing both string and numeric versions of your target value. This ensures you match documents regardless of how the data was stored (as string or number).