Here are the most frequently asked Power BI Interview Questions and Answers:
1. What is Power BI?
Power BI is a business analytics tool by Microsoft that helps to visualize data, share insights, and turn raw data into actionable insights through interactive dashboards and reports.
2. What are the components of Power BI?
- Power BI Desktop: A tool to create reports and dashboards.
- Power BI Service: An online SaaS (Software as a Service) platform to share and collaborate on reports.
- Power BI Mobile: Apps for mobile devices to view reports on the go.
- Power BI Gateway: Connects on-premise data sources with Power BI Service for real-time updates.
- Power BI Report Server: An on-premise server for hosting Power BI reports.
3. What is a dashboard in Power BI?
A dashboard is a single-page, often called a canvas, that shows visualizations or tiles based on one or more datasets. It provides a summary view and can be shared with others.
4. What is DAX in Power BI?
DAX stands for Data Analysis Expressions. It is a formula language used in Power BI to create custom calculations and logic, similar to Excel formulas.
5. What are the different types of filters in Power BI? Answer:
- Visual-level filters: Apply to a single visualization.
- Page-level filters: Apply to all the visualizations on a single page.
- Report-level filters: Apply to all pages in a report.
6. What is a calculated column in Power BI?
A calculated column is a new column that you add to a table using a DAX formula. It’s useful when you need to create new data from existing data in your dataset.
7. What is a Power Query?
Power Query is a data connection technology that allows you to discover, connect, combine, and refine data across a wide range of sources.
8. What is the difference between a calculated column and a measure in Power BI?
- Calculated Column: A new column created in a table using a DAX formula. The values are calculated row by row.
- Measure: A calculation performed on data aggregated over many rows. Measures are used in visualizations like totals, averages, and percentages.
9. What are Power BI dataflow?
Dataflows are a collection of tables created and managed in the Power BI service, where you can ingest, transform, and store data in a cloud environment.
10. What is the use of the Power BI gateway?
The Power BI Gateway is used to connect on-premise data sources securely with Power BI service, allowing for real-time data refreshes.
11. How do you create a relationship between tables in Power BI?
In Power BI, you can create relationships between tables by linking columns that have common data (like an ID or name). You do this in the “Model” view by dragging a line between the related columns.
12. What is row-level security (RLS) in Power BI?
RLS is a feature in Power BI that restricts data access for users based on roles. For example, a user can only see data related to their department.
13. What are the different views in Power BI Desktop?
- Report View: Create and view visualizations.
- Data View: View and explore the data in your tables.
- Model View: Create relationships between tables and manage your data model.
14. How can you share reports in Power BI?
You can share reports in Power BI through the Power BI Service by publishing reports to the web, sharing them directly with others via email, or by creating and sharing dashboards.
15. What is the difference between Power BI and Tableau?
Both are data visualization tools, but Power BI is more integrated with Microsoft products, offers more affordable pricing, and is easier for users who are already familiar with Microsoft tools. Tableau is known for its advanced visualization capabilities and flexibility but can be more complex and costly.
