Counting Documents in a MongoDB Collection

Review the following code, which demonstrates how to count the number of documents that match a query.

Count Documents

Use db.collection.countDocuments() to count the number of documents that match a query. countDocuments() takes two parameters: a query document and an options document.

Syntax:

db.collection.countDocuments( <query>, <options> )

The query selects the documents to be counted.

Examples:

// Count number of docs in trip collection
db.trips.countDocuments({})

// Count number of trips over 120 minutes by subscribers
db.trips.countDocuments({ tripduration: { $gt: 120 }, usertype: "Subscriber" })