$in for matching a set in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find documents where the field 'color' matches any value in the list.

MongoDB

db.collection.find({ color: { [1]: ["red", "blue", "green"] } })

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

A$ne

B$eq

C$in

D$gt

Attempts:

3 left

💡 Hint

Common Mistakes

Using $eq instead of $in will only match a single value, not a list.

Using $gt or $ne will not match multiple values as intended.

The $in operator matches any of the values specified in the array.

2fill in blank

medium

Complete the code to find documents where the 'status' field is either 'active' or 'pending'.

MongoDB

db.users.find({ status: { [1]: ["active", "pending"] } })

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

A$nin

B$in

C$exists

D$all

Attempts:

3 left

💡 Hint

Common Mistakes

Using $nin will exclude those values instead of including them.

Using $all requires the field to contain all listed values, which is not suitable here.

The $in operator matches documents where the field's value is in the specified array.

3fill in blank

hard

Fix the error in the query to correctly find documents where 'category' is one of the specified values.

MongoDB

db.products.find({ category: { [1]: ["electronics", "furniture"] } })

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

A$nin

B$eq

C$all

D$in

Attempts:

3 left

💡 Hint

Common Mistakes

Using $eq with multiple values causes syntax errors.

Not using an array for multiple values with $in causes errors.

The $in operator requires an array of values, so the values must be inside brackets [].

4fill in blank

hard

Fill both blanks to find documents where 'tags' contain any of the specified values.

MongoDB

db.articles.find({ tags: { [1]: ["mongodb", "database"], [2]: true } })

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

A$in

B$all

C$exists

D$nin

Attempts:

3 left

💡 Hint

Common Mistakes

Using $all instead of $in requires all values to be present, which is stricter.

Omitting $exists might include documents without the 'tags' field.

The $in operator matches any value in the array, and $exists: true ensures the 'tags' field exists.

5fill in blank

hard

Fill all three blanks to find documents where 'status' is in the list and 'score' exists and is greater than 50.

MongoDB

db.records.find({ status: { [1]: ["open", "closed"] }, score: { [2]: true, [3]: 50 } })

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

A$in

B$exists

C$gt

D$lt

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt instead of $gt will find scores less than 50.

Omitting $exists might include documents without a 'score' field.

$in matches status values, $exists: true ensures 'score' field exists, and $gt: 50 filters scores greater than 50.