sort method ascending and descending in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to sort the documents by age in ascending order.

MongoDB

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

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

A0

B-1

C1

Dasc

Attempts:

3 left

💡 Hint

Common Mistakes

Using -1 instead of 1 for ascending order.

Using 0 which does not sort.

Using 'asc' which is not valid in MongoDB.

In MongoDB, sorting in ascending order is done by using 1 as the value for the field in the sort method.

2fill in blank

medium

Complete the code to sort the documents by score in descending order.

MongoDB

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

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

A-1

B0

C1

Ddesc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of -1 for descending order.

Using 0 which does not sort.

Using 'desc' which is not valid in MongoDB.

Descending order in MongoDB sort is indicated by -1 for the field.

3fill in blank

hard

Fix the error in the code to sort by name in ascending order.

MongoDB

db.collection.find().sort({ name: [1] })

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

A'asc'

B'ascending'

Ctrue

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings instead of numbers for sort order.

Using boolean values which are invalid.

The sort method requires 1 for ascending order, not strings or booleans.

4fill in blank

hard

Fill both blanks to sort by age ascending and score descending.

MongoDB

db.collection.find().sort({ age: [1], score: [2] })

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

A1

B-1

C0

Dasc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 which does not sort.

Using strings like 'asc' or 'desc' which are invalid.

Use 1 for ascending and -1 for descending in MongoDB sort method.

5fill in blank

hard

Fill all three blanks to sort by name descending, age ascending, and score descending.

MongoDB

db.collection.find().sort({ name: [1], age: [2], score: [3] })

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

A1

B-1

C0

Dasc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 which does not sort.

Using strings instead of numbers for sort order.

Descending order is -1, ascending is 1. Use these values for each field in the sort method.

Practice

1. What does the sort({ age: 1 }) method do in MongoDB?

easy

A. Deletes documents with age less than 1

B. Sorts documents by age in descending order (largest to smallest)

C. Filters documents where age equals 1

D. Sorts documents by age in ascending order (smallest to largest)

Solution

1. Step 1: Understand the sort method parameter

   The number 1 in sort({ age: 1 }) means ascending order.

2. Step 2: Interpret the sorting effect

   Documents will be arranged from smallest age to largest age.

3. Final Answer:

   Sorts documents by age in ascending order (smallest to largest) -> Option D

4. Quick Check:

   sort({ field: 1 }) = ascending order [OK]

Hint: 1 means ascending order, -1 means descending order [OK]

Common Mistakes:

• Confusing 1 with descending order
• Thinking sort filters data
• Assuming sort deletes documents

2. Which of the following is the correct syntax to sort documents by score in descending order in MongoDB?

easy

A. db.collection.find().sort({ score: -1 })

B. db.collection.find().sort({ score: 1 })

C. db.collection.find().sort(score: -1)

D. db.collection.find().sort({ -1: score })

Solution

1. Step 1: Check the correct object syntax for sort

   The sort method requires an object with field name as key and 1 or -1 as value, inside curly braces.

2. Step 2: Identify descending order syntax

   Descending order is indicated by -1, so { score: -1 } is correct.

3. Final Answer:

   db.collection.find().sort({ score: -1 }) -> Option A

4. Quick Check:

   sort({ field: -1 }) = descending order [OK]

Hint: Use curly braces and colon: sort({ field: -1 }) [OK]

Common Mistakes:

• Missing curly braces around sort argument
• Using parentheses instead of braces
• Putting -1 as key instead of value

3. Given the documents: [{"name": "Anna", "score": 85}, {"name": "Ben", "score": 92}, {"name": "Cara", "score": 78}], what will be the order of names after running db.students.find().sort({ score: 1 })?

medium

A. ["Ben", "Anna", "Cara"]

B. ["Cara", "Ben", "Anna"]

C. ["Cara", "Anna", "Ben"]

D. ["Anna", "Cara", "Ben"]

Solution

1. Step 1: Understand ascending sort by score

   Sorting by score ascending means from smallest to largest score: 78, 85, 92.

2. Step 2: Map scores to names in order

   78 = Cara, 85 = Anna, 92 = Ben, so order is ["Cara", "Anna", "Ben"].

3. Final Answer:

   ["Cara", "Anna", "Ben"] -> Option C

4. Quick Check:

   sort({ score: 1 }) = ascending order [OK]

Hint: Ascending sort orders from smallest to largest [OK]

Common Mistakes:

• Mixing ascending with descending order
• Sorting by name instead of score
• Confusing array order in output

4. What is wrong with this MongoDB query?

db.products.find().sort({ price: 2 })

medium

A. The find() method cannot be chained with sort()

B. The sort value must be 1 or -1, not 2

C. The field name 'price' is invalid

D. Missing parentheses after sort

Solution

1. Step 1: Check valid sort values

   MongoDB sort only accepts 1 for ascending or -1 for descending, not 2.

2. Step 2: Identify the error cause

   Using 2 will cause a syntax or runtime error because it's invalid.

3. Final Answer:

   The sort value must be 1 or -1, not 2 -> Option B

4. Quick Check:

   sort values = 1 or -1 only [OK]

Hint: Sort values must be exactly 1 or -1 [OK]

Common Mistakes:

• Using numbers other than 1 or -1
• Assuming any positive number works
• Thinking sort can't chain after find()

5. You have a collection with documents containing category and price. How do you sort first by category ascending, then by price descending?

hard

A. db.collection.find().sort({ category: 1, price: -1 })

B. db.collection.find().sort({ price: -1, category: 1 })

C. db.collection.find().sort({ category: -1, price: 1 })

D. db.collection.find().sort({ category: 1 }).sort({ price: -1 })

Solution

1. Step 1: Understand multi-field sort syntax

   MongoDB sorts by fields in the order they appear in the object passed to sort().

2. Step 2: Apply ascending to category and descending to price

   Use { category: 1, price: -1 } to sort category ascending, then price descending within each category.

3. Final Answer:

   db.collection.find().sort({ category: 1, price: -1 }) -> Option A

4. Quick Check:

   Multi-field sort = object with fields in order [OK]

Hint: List fields in sort object in desired priority order [OK]

Common Mistakes:

• Reversing field order changes sort priority
• Trying to chain multiple sort() calls
• Using wrong sort values for fields