EXL Data Analyst Interview Experience:


SQL Questions

1. You have a table Transactions with columns TransactionID, CustomerID, Date, and Amount. Write a query to calculate the cumulative revenue per customer for each month in the last year.
2. A table Production contains columns PlantID, Date, and Output. Write a query to identify the plants that consistently exceeded their daily average output for at least 20 days in a given month.
3. In a table EmployeeAttendance with columns EmployeeID, Date, and Status (values: ‘Present’, ‘Absent’), write a query to find employees with the highest consecutive absences in the last quarter.
4. What are the pros and cons of using indexes in SQL, and when would you avoid using them?
5. Explain the differences between window functions and aggregate functions with examples.

Python Questions

6. Write a Python script to merge multiple CSV files from a directory into a single file and perform basic data cleaning.
7. Given a list of dictionaries, write a Python program to group the data by a specific key and calculate summary statistics for the grouped data.
8. Explain the difference between a list, a tuple, and a dictionary in Python, and provide examples of their usage.
9. Write a Python function to automate the generation of monthly reports from a dataset stored in an Excel file.

Power BI Questions

10. How would you create a dashboard in Power BI to track the operational efficiency of production plants?
11. Explain how you would handle a situation where the data source refresh in Power BI is causing delays.
12. What is the difference between row-level security and role-level security in Power BI?
13. How would you use Power BI to visualize trends and outliers in daily sales data?
14. Discuss how you would create a calculated measure to show YoY (Year-over-Year) growth in Power BI.

General Questions

15. Share an example where your data-driven insights helped solve a business problem or improve a process.
16. How do you prioritize tasks and manage deadlines in a high-pressure environment?