$gt and $gte for greater than in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find documents where the age is greater than 25.

MongoDB

db.collection.find({ age: { [1]: 25 } })

Drag options to blanks, or click blank then click option'

A$gt

B$lt

C$eq

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt which means 'less than'.

Using $eq which means 'equal to'.

The $gt operator means 'greater than'. So this query finds documents with age > 25.

2fill in blank

medium

Complete the code to find documents where the score is greater than or equal to 80.

MongoDB

db.collection.find({ score: { [1]: 80 } })

Drag options to blanks, or click blank then click option'

A$ne

B$lte

C$gte

D$lt

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt or $lte which mean less than or less than or equal.

Using $ne which means not equal.

The $gte operator means 'greater than or equal to'. This query finds documents with score >= 80.

3fill in blank

hard

Fix the error in the query to find documents where price is greater than 100.

MongoDB

db.collection.find({ price: { [1] 100 } })

Drag options to blanks, or click blank then click option'

A$gt:

B$lt:

C$gte:

D$eq:

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the colon after the operator.

Using $lt: which means less than.

The operator must be followed by a colon ':' inside the object. $gt: 100 means price > 100.

4fill in blank

hard

Fill both blanks to find documents where quantity is greater than 10 and less than 50.

MongoDB

db.collection.find({ quantity: { [1]: 10, [2]: 50 } })

Drag options to blanks, or click blank then click option'

A$gt

B$gte

C$lt

D$lte

Attempts:

3 left

💡 Hint

Common Mistakes

Using $gte instead of $gt for strict greater than.

Using $lte instead of $lt for strict less than.

Use $gt for greater than 10 and $lt for less than 50 to find quantity between 10 and 50.

5fill in blank

hard

Fill all three blanks to find documents where rating is greater than or equal to 4, price is less than 100, and stock is greater than 0.

MongoDB

db.collection.find({ rating: { [1]: 4 }, price: { [2]: 100 }, stock: { [3]: 0 } })

Drag options to blanks, or click blank then click option'

A$gt

B$lt

C$gte

D$lte

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up $gt and $gte operators.

Using $lte instead of $lt for price.

Use $gte for rating >= 4, $lt for price < 100, and $gt for stock > 0.

Practice

1. What does the $gt operator do in a MongoDB query?

easy

A. Finds documents where the field value is less than the specified value.

B. Finds documents where the field value is equal to the specified value.

C. Finds documents where the field value is strictly greater than the specified value.

D. Finds documents where the field value is greater than or equal to the specified value.

Solution

1. Step 1: Understand the meaning of $gt

   The $gt operator means "greater than" and selects values strictly larger than the given number.

2. Step 2: Compare with other operators

   $gte means "greater than or equal to", so it includes the number itself, unlike $gt.

3. Final Answer:

   Finds documents where the field value is strictly greater than the specified value. -> Option C

4. Quick Check:

   $gt = strictly greater than [OK]

Hint: Remember: $gt means strictly greater than [OK]

Common Mistakes:

• Confusing $gt with $gte
• Thinking $gt includes equal values
• Mixing $gt with less than operators

2. Which of the following is the correct syntax to find documents where the field age is greater than or equal to 18 in MongoDB?

easy

A. { age: { $gte: 18 } }

B. { age: { $gt: 18 } }

C. { age: { $gte: "18" } }

D. { age: { $gte: > 18 } }

Solution

1. Step 1: Check the operator and syntax

   The correct operator for "greater than or equal to" is $gte, and it must be used as { field: { $gte: value } }.

2. Step 2: Validate the value type and format

   The value should be a number (18), not a string or invalid syntax like > 18.

3. Final Answer:

   { age: { $gte: 18 } } -> Option A

4. Quick Check:

   Correct syntax uses $gte with number [OK]

Hint: Use { field: { $gte: number } } for greater or equal [OK]

Common Mistakes:

• Using quotes around numbers
• Writing invalid syntax like $gte: > 18
• Confusing $gt and $gte

3. Given the collection products with documents:

{ "name": "Pen", "price": 5 }

{ "name": "Notebook", "price": 10 }

{ "name": "Backpack", "price": 20 }

What will be the result of the query db.products.find({ price: { $gt: 10 } })?

medium

A. [{ "name": "Notebook", "price": 10 }, { "name": "Backpack", "price": 20 }]

B. [{ "name": "Pen", "price": 5 }]

C. []

D. [{ "name": "Backpack", "price": 20 }]

Solution

1. Step 1: Understand the query condition

   The query uses $gt: 10, so it selects documents where price is strictly greater than 10.

2. Step 2: Check each document's price

   "Pen" has price 5 (not > 10), "Notebook" has price 10 (not > 10), "Backpack" has price 20 (greater than 10).

3. Final Answer:

   [{ "name": "Backpack", "price": 20 }] -> Option D

4. Quick Check:

   Only price > 10 matches [OK]

Hint: Remember $gt excludes equal values [OK]

Common Mistakes:

• Including documents with price equal to 10
• Confusing $gt with $gte
• Selecting documents with price less than 10

4. You wrote the query db.users.find({ age: { $gte: 21 } }) but it returns no results even though some users are 21 or older. What is the likely problem?

medium

A. You should use $gt instead of $gte.

B. The field name age is misspelled in the documents.

C. The query syntax is incorrect; $gte cannot be used here.

D. MongoDB does not support $gte operator.

Solution

1. Step 1: Check the query syntax

   The syntax { age: { $gte: 21 } } is correct and supported by MongoDB.

2. Step 2: Consider data issues

   If no results appear, likely the field age is misspelled or missing in documents, so no matches occur.

3. Final Answer:

   The field name age is misspelled in the documents. -> Option B

4. Quick Check:

   Field name mismatch causes no results [OK]

Hint: Check field names carefully if no results [OK]

Common Mistakes:

• Assuming $gte is unsupported
• Switching $gte to $gt unnecessarily
• Ignoring possible typos in field names

5. You want to find all orders with a total amount greater than or equal to 100 but less than 200. Which MongoDB query correctly uses $gte and $gt to achieve this?

hard

A. { total: { $gte: 100, $lt: 200 } }

B. { total: { $gt: 100, $gte: 200 } }

C. { total: { $gte: 100, $gt: 200 } }

D. { total: { $gte: 100, $gt: 199 } }

Solution

1. Step 1: Understand the range conditions

   You want totals >= 100 and < 200, so use $gte: 100 and $lt: 200 (less than 200).

2. Step 2: Check each option's operators

   { total: { $gte: 100, $lt: 200 } } correctly uses $gte: 100 and $lt: 200. Other options misuse operators or values.

3. Final Answer:

   { total: { $gte: 100, $lt: 200 } } -> Option A

4. Quick Check:

   Use $gte for lower bound, $lt for upper bound [OK]

Hint: Use $gte for start, $lt for end of range [OK]

Common Mistakes:

• Using $gt instead of $gte for lower bound
• Using $gte for upper bound instead of $lt
• Mixing operator directions incorrectly