Data Science Interview Questions Section 3
Welcome to Section 3 of our Data Science Interview Questions series! In this part, we focus on key topics like SQL, Data Warehousing, and general analytics concepts — all critical areas for data science interviews and real-world projects. These 25 carefully selected questions will strengthen your understanding of database management, data storage strategies, and analytical thinking. Whether you’re revising for an upcoming interview or simply sharpening your expertise, this section will help you master important concepts with clarity. Let’s get started!
Also Read: Data Science Interview Questions Section 2: 25 Questions Designed To Deepen Your Understanding
Q. Which SQL clause is used to filter grouped results?
Answer: HAVING
Q. Which of these is a window function?
Answer: HAVING
Q. A fact table in a star schema typically contains:
Answer: HAVING
Q. In Snowflake, which layer stores the actual business logic and KPIs?
Answer: HAVING
Q. How do you prevent duplicate rows in SQL results?
Answer: HAVING
Q. In Power BI, which language is used for calculated columns and measures?
Answer: HAVING
Q. Which function retrieves the previous row value in SQL?
Answer: HAVING
Q. Which clause limits the number of records returned in SQL?
Answer: HAVING
Q. What does denormalization aim to do?
Answer: HAVING
Q. What is the primary purpose of indexing in databases?
Answer: HAVING
Q. Which SQL join returns all records when there is a match in either table?
Answer: HAVING
Q. To rank rows within a partition in SQL, you use:
Answer: SUM(Amount) OVER (PARTITION BY Region)
Q. Which file format is columnar and optimized for big data storage?
Answer: Parquet
Q. Which command removes duplicates from a SQL result set?
Answer: DISTINCT
Q. Which Snowflake feature helps to store previous versions of data?
Answer: Time Travel
Q. Which SQL keyword is used for conditional logic in SELECT statements?
Answer: CASE
Q. What type of join returns all combinations of records from both tables?
Answer: CROSS JOIN
Q. Which keyword combines results of two SELECT queries including duplicates?
Answer: UNION ALL
Q. What is the purpose of the CTE (Common Table Expression)?
Answer: To define temporary views for query readability
Q. Which type of index allows fast search on multiple columns in SQL?
Answer: Compound Index
Q. Which is the most optimized way to get the 2nd highest salary from a table?
Answer: SELECT MAX(salary) WHERE salary < (SELECT MAX(salary))
Q. Which clause is used to rename a column in SQL output?
Answer: AS
Q. Which Power BI tool transforms and cleanses data before loading?
Answer: Power Query Editor
Q. In Tableau, how do you define a hierarchy (e.g., Country > State > City)?
Answer: Drag one field over another in the data pane
Q. Which analytical function returns the rank of a value in a dataset without gaps?
Answer: DENSE_RANK()
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Hi, I’m Anuja Bisht, a recent graduate from DU SOL with a passion for digital marketing. I created Curious Club (curiousclub.in) to help you stay ahead of the job curve. My goal is to provide you with the latest job updates and resources, empowering you to land your dream career.
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