Medium-level general questions from real data engineering interviews.
These medium general questions are selected from real interviews at top companies. Each question includes a detailed expert answer and pro tip to help you nail your interview. This set leans toward the medium-difficulty band most real interviews actually live in (16 of 16). Recurring themes are partition, sql, and join — these patterns appear most often in real interviews and reward the deepest preparation. These questions have been reported across 17 companies including Infosys and Deolite. Average answer is around 1 minute of reading — plan roughly 1 hour to work through the full set thoughtfully.
This collection contains 16 curated questions: 0 easy, 16 medium. The balanced mix of difficulties makes this set suitable for engineers at any career stage.
The most frequently tested areas in this set are partition (9), sql (9), join (8), spark (5), window (4), and etl (2). Focusing on these topics will give you the highest return on your preparation time.
Medium-difficulty questions form the bulk of real interviews — spend the most time here and practice explaining your reasoning out loud. For each question, try answering before revealing the solution. Use our AI Mock Interview to simulate real interview conditions and get instant feedback on your responses.
How would you read data from a web API? What steps would you follow after reading the data?
What is the difference between SQL and NoSQL databases?
Calculate a 7-day moving average of orders for each city in the Swiggy database.
Calculate the total number of transactions (units sold) for each product.
Data Shuffling Causes and Techniques
Describe the concept of data sharding and when to use it.
Fetch the rows with the highest scores for each student in a year.
Find All Numbers that Appear at Least Three Times Consecutively
Find the names of managers who have at least 7 employees directly reporting to them.
Find top 3 products sold based on total quantity.
Given the data with id, name, and department, how would you calculate how many employees are in each department?
How does cluster size impact parallelism limits?
How would you optimize a slow-running SQL query?
How would you implement custom alarms for data delays or job failures?
Reverse operation for splitting values back to original format
Shell commands for renaming a file?
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