Find Documents

Introduction

find() is the read primitive. It returns a cursor; you chain modifiers like .sort(), .limit(), .skip(), .project() to refine it. Mastering find is mastering 80% of day-to-day MongoDB work.

Understanding the topic

• find(filter, projection) — returns cursor.
• findOne — returns the first match (or null).
• Cursors are lazy — nothing executes until you iterate.
• Indexes turn O(n) scans into O(log n) lookups.

Syntax reference

db.users.find({ city: "NYC" })
  .sort({ createdAt: -1 })
  .limit(20)
  .project({ name: 1, email: 1, _id: 0 });

db.orders.findOne({ _id: ObjectId("...") });

Real-world use

Listing endpoints in every REST API map to a single find with filter + sort + limit + projection.

Best practices

• Always project only the fields you need.
• Always .limit() list queries.