MongoDB

Query Commands

MongoDB query language offers powerful operators for filtering, comparing, and selecting documents.

8 commands

Pro Tips

Use projection to return only needed fields, reducing network and memory usage.

Prefix regex patterns (^pattern) can use indexes for faster searches.

Commands

Comparison operators

$ db.users.find({ age: { $gte: 18, $lte: 65 } })

Use $gt, $gte, $lt, $lte, $eq, $ne.

Logical AND

$ db.users.find({ $and: [{ age: { $gt: 20 } }, { status: "active" }] })

Match all conditions.

Logical OR

$ db.users.find({ $or: [{ age: { $lt: 20 } }, { status: "vip" }] })

Match any condition.

In array

$ db.users.find({ role: { $in: ["admin", "moderator"] } })

Match any value in array.

Regex search

$ db.users.find({ name: { $regex: /^john/i } })

Pattern matching with regex.

Field exists

$ db.users.find({ email: { $exists: true } })

Check if field exists.

Projection

$ db.users.find({}, { name: 1, email: 1, _id: 0 })

Select specific fields to return.

Sort and limit

$ db.users.find().sort({ age: -1 }).limit(10)

Sort descending and limit results.