Combining logical and comparison operators in MongoDB

Introduction

We combine logical and comparison operators to find data that meets multiple conditions at once. This helps us get exactly the information we want.

Finding users who are older than 18 and live in a specific city.

Getting products that cost less than $50 or are on sale.

Selecting orders that are either pending or were placed in the last week.

Filtering books that have more than 300 pages and are written by a certain author.

Syntax

MongoDB

{ $and: [ { field1: { $operator: value } }, { field2: { $operator: value } } ] }

{ $or: [ { field1: { $operator: value } }, { field2: { $operator: value } } ] }

$and means all conditions must be true.

$or means at least one condition must be true.

Examples

Finds documents where age is greater than 18 and city is New York.

MongoDB

{ $and: [ { age: { $gt: 18 } }, { city: "New York" } ] }

Finds documents where price is less than 50 or the item is on sale.

MongoDB

{ $or: [ { price: { $lt: 50 } }, { onSale: true } ] }

Finds books with more than 300 pages and written by Jane Doe.

MongoDB

{ $and: [ { pages: { $gt: 300 } }, { author: "Jane Doe" } ] }

Sample Program

This query finds all products in the 'electronics' category that cost less than 100.

MongoDB

db.products.find({
  $and: [
    { price: { $lt: 100 } },
    { category: "electronics" }
  ]
})

Important Notes

You can combine many conditions inside $and or $or arrays.

If you only use $and, you can also write conditions directly without $and, because MongoDB treats multiple conditions as AND by default.

Logical operators help you build flexible and precise queries.

Summary

Logical operators like $and and $or combine multiple conditions.

Comparison operators like $gt (greater than) and $lt (less than) check values.

Use them together to find exactly the data you want.