How do you handle NULL values in SQL? Mention functions like COALESCE and ISNULL.
SQLmedium
2
How do you optimize a long-running SQL query?
SQLhard
3
How would you handle duplicate records in an SQL table?
SQLmedium
4
Write a SQL query to find top 3 earners in each department.
SQLmedium
5
Design a Delta table layout for mixed workload: point lookups by user_id, range scans by date, and full partition scans. Compare partitioning vs. Z-ordering—when to use each, and the rewrite cost trade-off.
Spark/Big Datahard
6
Architect incremental load in ADF + Databricks with idempotency, late-arrival handling, and cost/scalability implications of watermark vs. change data capture.
Spark/Big Datamedium
7
What is the small-file problem in Spark, and how do you solve it?
Spark/Big Datahard
8
What is the difference between Managed and External Tables in Databricks?
Spark/Big Dataeasy
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