SQL questions from Citi data engineering interviews.
These sql questions are sourced from Citi data engineering interviews. Each includes an expert-level answer. This set leans toward the medium-difficulty band most real interviews actually live in (7 of 8). Recurring themes are partition, join, and spark — these patterns appear most often in real interviews and reward the deepest preparation. Many of these questions also surface at Coforge and HCL, so the preparation transfers across companies. Average answer is around 1 minute of reading — plan roughly 1 hour to work through the full set thoughtfully.
This collection contains 8 curated questions: 1 easy, 7 medium. There's a strong foundation of fundamentals-focused questions — ideal for building confidence before tackling advanced topics.
The most frequently tested areas in this set are partition (6), join (4), spark (2), and window (2). Focusing on these topics will give you the highest return on your preparation time.
Start with the easy questions to warm up and solidify fundamentals. 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.
What is the difference between partitioning and bucketing in Spark, and when would you use bucketing?
What is a window function? Explain with an example.
How to view Oozie jobs?
Oozie join condition?
Partitioning a table with card details and transactions?
Teradata to Hadoop migration and handling data with SCD Type 2?
What is a Kafka topic, and how do you choose the number of partitions for it?
What is the role of a partition in Kafka, and how does it impact scalability?
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