Top Power BI Interview Questions and Answers

Power BI is a business intelligence (BI) tool developed by Microsoft that helps businesses to analyze data and create interactive dashboards and reports. It can connect to a wide variety of data sources, including Excel, SQL Server, and cloud-based data warehouses.

Here are top Power BI interview questions,

 

1. What is Power BI, and what are its components?

Power BI is a business analytics service by Microsoft that provides interactive visualizations and business intelligence capabilities with an easy-to-use interface.

Components:

- Power BI Desktop: Used for creating reports and dashboards.

- Power BI Service (Power BI Online): For publishing, sharing, and collaborating on reports.

- Power BI Mobile: Enables access to reports and dashboards on mobile devices.

- Power BI Gateway: Connects on-premises data sources to Power BI Service.

- Power BI Embedded: Allows developers to embed Power BI content in applications.

 

2. What is a Power BI data model, and how is it created?

A Power BI data model is a collection of data tables, relationships, calculations, and hierarchies used to create reports and visuals. It's created in Power BI Desktop by importing data, transforming it, and defining relationships between tables.

 

3. Explain the difference between Power BI Desktop and Power BI Service.

- Power BI Desktop: Used for report and dashboard creation, data modeling, and data transformation. It's a Windows application.

- Power BI Service: For publishing, sharing, and collaborating on reports in a web-based environment. Users can view reports and dashboards via a web browser or the mobile app.

 

4. How can you import data into Power BI?

Data can be imported into Power BI from various sources, including databases, Excel files, web services, and more. Common methods include using Power Query for data transformation and loading data from the Home tab in Power BI Desktop.

 

5. What is Power Query, and what is its role in Power BI?

Power Query is a data transformation and manipulation tool in Power BI. It allows users to connect to various data sources, clean and transform data, and load it into the data model. Power Query ensures data is prepared for analysis.

 

6. What is difference between Power BI and Tableau

Here's a brief summary of the key differences between Power BI and Tableau:

Vendor and Licensing:

   - Power BI is developed by Microsoft, while Tableau is developed by Tableau Software.

   - Power BI offers various licensing options, including free and subscription-based plans.

   - Tableau has creator, user, and core-based licensing models.

Ease of Use:

   - Power BI is known for its user-friendly interface, making it accessible to a broader audience.

   - Tableau, while user-friendly, may have a slightly steeper learning curve for complex data analysis.

Data Preparation:

   - Power BI uses Power Query for data preparation and transformation.

   - Tableau offers data preparation capabilities through Tableau Prep, a separate tool.

Data Modeling and Calculations:

   - Power BI uses DAX (Data Analysis Expressions) for calculations and modeling.

   - Tableau uses Tableau Calculation Language (TCL) for calculations.

Data Visualization:

   - Both tools offer extensive visualization options, but Power BI emphasizes responsive and interactive visuals.

   - Tableau has a strong community for sharing custom visualizations.

Collaboration and Sharing:

   - Power BI Service and Tableau Server/Online enable cloud-based collaboration and sharing.

   - Tableau offers robust content management and permissions.

Pricing:

   - Power BI has free, user-based, and capacity-based pricing.

   - Tableau requires creator licenses for desktop, and its server and online versions are priced based on users or cores.

 

7. Explain the importance of DAX (Data Analysis Expressions) in Power BI.

DAX is a formula language used in Power BI for creating custom calculations and aggregations. It's crucial for adding calculated columns, measures, and performing advanced calculations in the data model.

 

8. What are calculated columns and measures in Power BI, and how do they differ?

- Calculated Columns: These are columns created in a table using DAX expressions. They store calculated values for each row in the table and can be used for filtering and sorting.

- Measures: Measures are DAX calculations that aggregate data. They return a single value and are used for summarizing data in visuals and calculations.

 

9. What is a slicer in Power BI, and how does it work?

A slicer is a visual element that allows users to filter data in a report. Users can select values from the slicer, and it dynamically filters visuals in the report based on the selected values.

 

10. How can you share a Power BI report with others?

Reports can be shared through the Power BI Service. You can publish a report to the Power BI Service, configure sharing options, and share it with specific users or groups. Alternatively, you can embed reports in websites or applications.

 

11. What is Power BI Gateway, and when is it used?

Power BI Gateway is a bridge that connects on-premises data sources to Power BI Service. It's used when you need to refresh data from sources behind a corporate firewall, such as databases or files on local servers.

 

12. How can you schedule data refresh in Power BI Service?

You can schedule data refresh in Power BI Service by configuring dataset settings. Scheduled refresh ensures that data in the Power BI Service stays up to date with the source data.

 

13. What are the different visualization types available in Power BI?

Power BI offers a wide range of visualization types, including bar charts, line charts, pie charts, tables, maps, scatter plots, cards, and custom visuals. The choice of visualization type depends on the data and the story you want to convey.

 

14. How do you create a drill-through in Power BI reports?

To create a drill-through experience, you define a drill-through page and add drill-through fields. Users can right-click on data points in a visual and choose "Drill Through" to navigate to the drill-through page and see detailed information.

 

15. What is the purpose of Power BI Apps?

Power BI Apps allow you to bundle a collection of dashboards, reports, and datasets into a single package for distribution. It's useful for sharing a set of related reports and visuals with others.

 

16. Explain the concept of row-level security in Power BI.

Row-level security in Power BI restricts data access based on user roles and filters applied to tables. It ensures that users can only see data relevant to their role, enhancing data security.

 

17. What is Power BI Embedded, and when is it used?

Power BI Embedded is a feature that allows developers to embed Power BI reports and visuals into custom applications or websites. It's used when you want to integrate Power BI content seamlessly within your own application's user interface.

 

18. What is Power BI Q&A, and how does it work?

Power BI Q&A is a natural language querying feature that allows users to ask questions in plain language and get answers in the form of interactive visuals. It uses advanced algorithms to understand user queries and generate corresponding visualizations.

 

19. How can you optimize Power BI reports for performance?

To optimize Power BI reports for performance, you can:

- Reduce the number of visuals on a page.

- Limit the use of high-cardinality visuals.

- Optimize DAX calculations.

- Use DirectQuery or Live Connection for large datasets.

- Implement effective caching strategies.

 

20. What is the difference between Power BI Pro and Power BI Premium?

- Power BI Pro: It is a per-user subscription that allows individuals to create, publish, and share reports. Each user needs a Pro license to access shared content.

- Power BI Premium: It is a dedicated capacity-based offering designed for organizations. With Premium, an organization purchases capacity, and users can access and share reports without needing individual Pro licenses. It also provides enhanced performance and features like AI capabilities.

 

Above are few top Power BI interview questions. Remember to prepare and expand on these answers.

Good luck with your interview! 👍