The interview process had three rounds:

• An online technical assessment
• A technical interview
• An HR discussion

The technical round focused on SQL joins, Python data manipulation, and Apache Spark. The HR round covered project experience, notice period, and communication skills. Overall, the experience was fair and well-structured.

Interview questions:

Q1: What is the difference between INNER JOIN and LEFT JOIN in SQL? A: INNER JOIN returns only matching records from both tables, while LEFT JOIN returns all records from the left table and matching ones from the right.

Q2: Explain how you optimized Spark jobs in your previous project. A: I optimized Spark jobs by using DataFrame APIs instead of RDDs, partitioning large datasets, caching reused data, and adjusting shuffle partitions for better performance.

Q3: How do you handle missing values in a dataset using Python? A: I usually handle missing values using pandas — by filling them with mean/median values or dropping rows/columns depending on the data importance.