PySpark Certification Practice Test 04

Window Functions and Analytical Processing

Question 1 of 20

📋 Multiple Choice

Question 61

An interviewer says: "A retail company wants the latest order for every customer. The source table contains multiple orders per customer." Which function would most likely be used?

A. sum()

B. count()

C. distinct()

✓

D. row_number()

Answer

✅ D. row_number()

Explanation

### Explanation row_number() is commonly used with partitionBy(customer_id) and ordered by order_date desc to identify the latest record.

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PySpark Certification Practice Test 04

Window Functions and Analytical Processing

Insightful Saga — Modern Data Engineering Certification Preparation

Question 61

An interviewer says: "A retail company wants the latest order for every customer. The source table contains multiple orders per customer." Which function would most likely be used?

A. sum()

B. count()

C. distinct()

D. row_number()

Answer: ✅ D. row_number()

Explanation:

### Explanation row_number() is commonly used with partitionBy(customer_id) and ordered by order_date desc to identify the latest record.

Question 62

An interviewer observes: "The finance team wants employees ranked by salary within each department. If two employees have the same salary, they should receive the same rank, and the next rank should be skipped." Which function matches this requirement?

A. dense_rank()

B. row_number()

C. lag()

D. rank()

Answer: ✅ D. rank()

Question 63

Observation: "A telecom company wants rankings without gaps even when values tie." Which function should be recommended?

A. dense_rank()

B. rank()

C. row_number()

D. count()

Answer: ✅ A. dense_rank()

Question 64

Observation: "A healthcare analyst wants to compare today's patient count with yesterday's patient count." Which function is most appropriate?

A. lag()

B. distinct()

C. lead()

D. rank()

Answer: ✅ A. lag()

Question 65

Observation: "A retail company wants to view the next scheduled delivery date for each shipment." Which function should be considered?

A. lag()

B. row_number()

C. avg()

D. lead()

Answer: ✅ D. lead()

Question 66

An interviewer asks: "Which function would you use to find the most recent transaction per customer?"

A. dense_rank()

B. row_number()

C. sum()

D. max()

Answer: ✅ B. row_number()

Question 67

Observation: "A bank wants a running account balance after every transaction." Which window function pattern is typically used?

A. dropDuplicates()

B. collect()

C. sum() over Window

D. distinct()

Answer: ✅ C. sum() over Window

Question 68

Observation: "A sales manager wants cumulative sales as each day passes." Which approach should be used?

A. Union

B. Left Join

C. Running Total Window

D. Distinct

Answer: ✅ C. Running Total Window

Question 69

Observation: "A customer can have multiple records. We only want the newest record." Which pattern is most commonly used?

A. collect()

B. row_number() = 1

C. count() = 1

D. distinct()

Answer: ✅ B. row_number() = 1

Question 70

Observation: "A company wants the Top 3 products by revenue within each country." Which capability best supports this?

A. fillna()

B. Window + rank()

C. dropDuplicates()

D. union()

Answer: ✅ B. Window + rank()

Question 71

An interviewer reviews a solution: ```python Window.partitionBy("department") ``` What business requirement is most likely being addressed?

A. Reading CSV files

B. Broadcasting data

C. Creating partitions in storage

D. Ranking within groups

Answer: ✅ D. Ranking within groups

Question 72

Observation: "A logistics company wants to compare current shipment cost with previous shipment cost." Which function is most suitable?

A. lead()

B. max()

C. lag()

D. count()

Answer: ✅ C. lag()

Question 73

Observation: "A manufacturing company wants the next machine maintenance date for every machine." Which function would help?

A. sum()

B. avg()

C. lead()

D. lag()

Answer: ✅ C. lead()

Question 74

Observation: "A company wants to identify the first transaction for every customer." Which function is commonly used?

A. distinct()

B. collect()

C. row_number()

D. union()

Answer: ✅ C. row_number()

Question 75

Observation: "A retailer wants to know how much sales changed compared to the previous day." Which function is most likely used?

A. cache()

B. lag()

C. countDistinct()

D. dense_rank()

Answer: ✅ B. lag()

Question 76

Observation: "Employees must be ranked by performance score. Employees with equal scores should receive consecutive rankings without gaps." Which function fits best?

A. dense_rank()

B. rank()

C. lead()

D. lag()

Answer: ✅ A. dense_rank()

Question 77

Observation: "A fraud analytics team wants the previous transaction amount available in every record." Which function is appropriate?

A. distinct()

B. row_number()

C. lead()

D. lag()

Answer: ✅ D. lag()

Question 78

Observation: "A business wants the next upcoming customer renewal date visible in the current row." Which function should be applied?

A. lead()

B. lag()

C. rank()

D. sum()

Answer: ✅ A. lead()

Question 79

Observation: "A company wants the Top 5 customers by yearly spending." Which window-based approach is most common?

A. union()

B. rank()/dense_rank() + filter

C. collect()

D. fillna()

Answer: ✅ B. rank()/dense_rank() + filter

Question 80

A Senior PySpark Interviewer makes the following observation: "Most real-world analytics problems involving latest records, ranking, comparisons, trends, Top-N reporting, and cumulative calculations are solved using Window Functions." How should this statement be evaluated?

A. Correct

B. Incorrect

Answer: ✅ A. Correct

Explanation:

### Explanation Window Functions are among the most important PySpark features for analytical workloads and are heavily used in enterprise reporting, customer analytics, finance, telecom, retail, and healthcare projects. --- --- title: PySpark Certification Practice Test 05 description: Production Project Walkthrough Scenarios --- # PySpark Certification Practice Test 05