Why query patterns matter in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

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

MongoDB

db.users.find({"age": {"$gt": [1])

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

A20

B25

C30

D15

Attempts:

3 left

💡 Hint

Common Mistakes

Using a smaller number like 15 will include too many results.

Using $lt instead of $gt will find ages less than the number.

The $gt operator means 'greater than'. We want ages greater than 25, so the value should be 25.

2fill in blank

medium

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

MongoDB

db.users.find({"status": {"$in": [1])

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

A["active", "pending"]

B["active"]

C["inactive", "pending"]

D["pending", "deleted"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one status will miss some results.

Using wrong statuses will return no results.

The $in operator checks if the field matches any value in the array. We want 'active' or 'pending', so the array should include both.

3fill in blank

hard

Fix the error in the query to find users with name starting with 'J'.

MongoDB

db.users.find({"name": [1])

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

A"^J"

B"J"

C/^J/

D/J$/

Attempts:

3 left

💡 Hint

Common Mistakes

Using a plain string 'J' matches exact name only.

Using /J$/ matches names ending with J, not starting.

To find names starting with 'J', use a regular expression /^J/. This matches strings beginning with 'J'.

4fill in blank

hard

Fill both blanks to find users older than 30 and with status 'active'.

MongoDB

db.users.find({"age": {"$gt": [1], "status": [2])

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

A30

B"active"

C"pending"

D25

Attempts:

3 left

💡 Hint

Common Mistakes

Using 25 instead of 30 for age.

Using 'pending' instead of 'active' for status.

The age should be greater than 30, so 30 is correct. The status should be exactly 'active', so use the string "active".

5fill in blank

hard

Fill all three blanks to find users with age less than 40, status 'pending', and name containing 'an'.

MongoDB

db.users.find({"age": {"[1]": [2], "status": "pending", "name": [3])

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

A$lt

B40

C/an/

D$gt

Attempts:

3 left

💡 Hint

Common Mistakes

Using $gt instead of $lt.

Using a string instead of regex for name.

Use $lt for 'less than' and 40 as the age limit. The name should match the regex /an/ to find 'an' anywhere in the name.