MongoDB Comparison Operators Practice Questions with Solutions

By /

Introduction

MongoDB comparison operators help you find documents by comparing field values. They are especially useful when you need records where a value is greater than, less than, equal to, or different from another value. In this chapter, you will practice MongoDB comparison operators such as $eq, $ne, $gt, $gte, $lt, $lte, $in, and $nin using simple, practical queries. MongoDB Comparison Operators Practice Questions with Solutions to help you understand the concepts.

Q1. Find Students Older Than 15

Problem Statement

Find all students whose age is greater than 15.

MongoDB Command / Query

db.students.find({
  age: { $gt: 15 }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Aman", age: 18, course: "Java" }
]

Explanation

$gt means greater than.

The query returns students where:

age > 15

Q2. Find Students Aged 16 or Older

Problem Statement

Find all students whose age is greater than or equal to 16.

MongoDB Command / Query

db.students.find({
  age: { $gte: 16 }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Aman", age: 18, course: "Java" }
]

Explanation

$gte means greater than or equal to.

So the query finds:

age >= 16

Q3. Find Students Younger Than 18

Problem Statement

Find all students whose age is less than 18.

MongoDB Command / Query

db.students.find({
  age: { $lt: 18 }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Priya", age: 15, course: "JavaScript" }
]

Explanation

$lt means less than.

The query searches for:

age < 18

Q4. Find Students Aged 17 or Younger

Problem Statement

Find all students whose age is less than or equal to 17.

MongoDB Command / Query

db.students.find({
  age: { $lte: 17 }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Priya", age: 15, course: "JavaScript" }
]

Explanation

$lte means less than or equal to.

So MongoDB finds:

age <= 17

Q5. Find Students Exactly 16 Years Old

Problem Statement

Find all students whose age is exactly 16.

MongoDB Command / Query

db.students.find({
  age: { $eq: 16 }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" }
]

Explanation

$eq means equal to.

This query finds documents where:

age = 16

For simple equality, you can also write:

db.students.find({ age: 16 })

Q6. Find Students Whose Age Is Not 16

Problem Statement

Find all students whose age is not equal to 16.

MongoDB Command / Query

db.students.find({
  age: { $ne: 16 }
})

Expected Output

[
  { name: "Priya", age: 15, course: "JavaScript" },
  { name: "Aman", age: 18, course: "Java" }
]

Explanation

$ne means not equal to.

The query excludes students whose age is 16.

Q7. Find Students Taking Python or Java

Problem Statement

Find students whose course is either Python or Java.

MongoDB Command / Query

db.students.find({
  course: { $in: ["Python", "Java"] }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Aman", age: 18, course: "Java" }
]

Explanation

$in checks whether a field matches any value from a specified list.

Here MongoDB searches for:

course = Python
OR
course = Java

Q8. Find Students Not Taking Python or Java

Problem Statement

Find students whose course is neither Python nor Java.

MongoDB Command / Query

db.students.find({
  course: { $nin: ["Python", "Java"] }
})

Expected Output

[
  { name: "Priya", age: 15, course: "JavaScript" },
  { name: "Neha", age: 17, course: "C++" }
]

Explanation

$nin means not in.

It excludes documents where course is "Python" or "Java".

Q9. Find Students Between Age 15 and 17

Problem Statement

Find students whose age is between 15 and 17, including both 15 and 17.

MongoDB Command / Query

db.students.find({
  age: {
    $gte: 15,
    $lte: 17
  }
})

Expected Output

[
  { name: "Priya", age: 15, course: "JavaScript" },
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Neha", age: 17, course: "C++" }
]

Explanation

Two comparison operators are used:

  • $gte: 15 → age must be 15 or greater
  • $lte: 17 → age must be 17 or less

Therefore:

15 <= age <= 17

Q10. Find Students Older Than 15 and Not Taking Java

Problem Statement

Find students whose age is greater than 15 and whose course is not Java.

MongoDB Command / Query

db.students.find({
  age: { $gt: 15 },
  course: { $ne: "Java" }
})

Expected Output

[
  { name: "Rahul", age: 16, course: "Python" },
  { name: "Neha", age: 17, course: "C++" }
]

Explanation

This query applies two conditions:

age > 15
AND
course != Java

Both conditions must be satisfied for a document to be returned.

Key Takeaways

  • $eq means equal to.
  • $ne means not equal to.
  • $gt means greater than.
  • $gte means greater than or equal to.
  • $lt means less than.
  • $lte means less than or equal to.
  • $in matches any value from a specified list.
  • $nin excludes values from a specified list.
  • Multiple comparison operators can be used together.
  • Comparison operators are commonly used with find(), updateMany(), and deleteMany() filters.

FAQs

1. What are comparison operators in MongoDB?

MongoDB comparison operators are query operators used to compare field values with specified values. Examples include $gt, $gte, $lt, $lte, $eq, and $ne.

2. What does $gt mean in MongoDB?

$gt means greater than.

db.students.find({ age: { $gt: 18 } })

This finds students whose age is greater than 18.

3. What is the difference between $gt and $gte?

$gt means greater than, while $gte means greater than or equal to.

$gt  → age > 18
$gte → age >= 18

4. What is the difference between $lt and $lte?

$lt means less than, while $lte means less than or equal to.

$lt  → age < 18
$lte → age <= 18

5. What is the use of $in in MongoDB?

$in is used when you want to match a field against multiple possible values.

db.students.find({
  course: { $in: ["Python", "Java"] }
})

6. What is the use of $nin in MongoDB?

$nin means not in. It finds documents whose field value does not match any value in the specified list.

db.students.find({
  course: { $nin: ["Python", "Java"] }
})

7. Can multiple comparison operators be used in one MongoDB query?

Yes. You can combine multiple comparison operators to create a more specific filter.

db.students.find({
  age: { $gte: 15, $lte: 17 }
})

This finds students whose age is between 15 and 17, including both values.

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

Related Posts

Scroll to Top