MongoDB query to count records on the basis of matching criteria

To count records on the basis of matching criteria in MongoDB, use the countDocuments() method with a query filter. This method returns the number of documents that match the specified criteria.

Syntax

db.collection.countDocuments({field1: value1, field2: value2})

Sample Data

Let us create a collection with documents ?

db.demo205.insertMany([
    {
        "id": "101",
        "Name": "",
        "Age": "",
        "isActive": false
    },
    {
        "id": "102", 
        "Name": "Chris",
        "Age": "25",
        "isActive": true
    },
    {
        "id": "103",
        "Name": "",
        "Age": "",
        "isActive": false
    }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e3d8a3003d395bdc21346eb"),
        ObjectId("5e3d8a3003d395bdc21346ec"), 
        ObjectId("5e3d8a3003d395bdc21346ed")
    ]
}

Display all documents from the collection ?

db.demo205.find();

{ "_id": ObjectId("5e3d8a3003d395bdc21346eb"), "id": "101", "Name": "", "Age": "", "isActive": false }
{ "_id": ObjectId("5e3d8a3003d395bdc21346ec"), "id": "102", "Name": "Chris", "Age": "25", "isActive": true }
{ "_id": ObjectId("5e3d8a3003d395bdc21346ed"), "id": "103", "Name": "", "Age": "", "isActive": false }

Example

Count documents where Name and Age are empty strings and isActive is false ?

db.demo205.countDocuments({
    Name: "",
    Age: "",
    "isActive": false
});

2

Key Points

• Use countDocuments() instead of deprecated count() method for better accuracy.
• Multiple criteria are combined with AND logic by default.
• Empty query {} counts all documents in the collection.

Conclusion

The countDocuments() method efficiently counts documents matching specific criteria. It provides accurate results and should be used instead of the deprecated count() method.