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Power BI Interview Questions

Power BI interview Questions

Power BI Interview Questions

Power BI Interview Questions

1. What is Power BI?

Power BI is a business analytics tool by Microsoft that enables users to visualize data, share insights, and make data-driven decisions. It includes features for data preparation, data modeling, and sharing interactive reports.

 

2. What are the different components of Power BI?

  • Power BI Desktop: A Windows application used for creating reports and data models.
  • Power BI Service: A cloud service for publishing, sharing, and collaborating on reports.
  • Power BI Mobile: Apps for accessing reports on mobile devices.
  • Power BI Gateway: Allows data to be transferred between on-premises data sources and the Power BI service.
  • Power BI Embedded: For integrating Power BI reports into custom applications.
 

3. What is Power Query?

Power Query is a data connection tool that allows you to import, transform, and clean data from various sources. It uses the M language for data transformation.

 

4. What is DAX in Power BI?

DAX (Data Analysis Expressions) is a formula language used for creating calculated columns, measures, and custom tables in Power BI. It enables advanced data analysis and aggregation.

 

5. Explain the difference between Power BI and Excel.

Power BI is designed for business intelligence, providing better capabilities for interactive data visualization, sharing, and reporting, while Excel is a general-purpose tool focused on data analysis and calculation.

 

6. What are calculated columns and measures in Power BI?

  • Calculated Columns: Columns that are computed during data load and are part of the data model.
  • Measures: Aggregated calculations (e.g., SUM, AVERAGE) calculated dynamically at query time based on filters or slicers.
 

7. What are the types of relationships in Power BI?

  • One-to-One: One record in a table relates to one record in another.
  • One-to-Many: One record in a table relates to multiple records in another.
  • Many-to-Many: Multiple records in one table relate to multiple records in another.
 

8. What is the difference between DirectQuery and Import mode?

  • DirectQuery: Data is queried live from the source, without being imported into Power BI, ensuring real-time data but with performance limitations.
  • Import Mode: Data is imported into Power BI, which improves performance but may not reflect real-time data.
 

9. What is Power BI Gateway?

Power BI Gateway is a bridge that facilitates the transfer of data between on-premises data sources and Power BI in the cloud. It can operate in two modes: Personal and Enterprise.

 

10. What is the difference between a slicer and a filter in Power BI?

  • Slicer: A visual element that allows users to filter data interactively on reports.
  • Filter: Can be applied at different levels (visual, page, or report) to restrict data used in visuals.
 

11. What is a Power BI Dashboard?

A dashboard is a collection of visuals (charts, graphs, tables) that provide a snapshot of key performance indicators (KPIs) and important data metrics.

 

12. What is the Power BI Service?

The Power BI Service is a cloud-based platform that allows you to publish, share, and collaborate on Power BI reports and dashboards with others.

 

13. What are Power BI Tiles?

Tiles are individual visual elements within a dashboard that represent a single piece of data, such as a chart or KPI.

 

14. What is a Power BI Report?

A report is a collection of visualizations (charts, tables, etc.) based on a single dataset. It can span multiple pages and offer detailed analysis.

 

15. What is Power BI Row-Level Security (RLS)?

Row-Level Security is used to restrict data access for certain users by filtering the data at the row level based on user roles.

 

16. How do you handle performance issues in Power BI?

To improve performance, you can:

  • Optimize data models.
  • Use DirectQuery only when necessary.
  • Reduce the number of visuals on a report page.
  • Limit complex DAX measures and queries.
  • Use aggregations to speed up large datasets.
 

17. What is a Measure in Power BI?

A measure is a dynamic calculation in Power BI that aggregates data based on the context of the report, such as a sum or average.

 

18. What are Power BI Visualizations?

Visualizations are graphical representations of data, including charts, tables, maps, and gauges, which help in understanding the data insights easily.

 

19. What is the use of Power BI Template?

Power BI templates allow you to save and share report layouts, including visualizations, queries, and connections, making it easier to replicate reports with different datasets.

 

20. What are custom visuals in Power BI?

Custom visuals are user-defined, third-party visuals that can be imported into Power BI to provide additional visualizations not available in the default set.

 

21. What are calculated tables in Power BI?

Calculated tables are tables that are created by DAX expressions, which are evaluated at the time the model is processed. They are used for more advanced data modeling.

 

22. What are bookmarks in Power BI?

Bookmarks capture the current state of a report page (filters, slicers, and visuals) and allow you to save and navigate between different views or layouts of a report.

 

23. Explain the Power BI Q&A feature.

Q&A allows users to ask natural language questions (e.g., “Total sales by region”) and automatically generate visuals based on the response.

 

24. How does Power BI handle date tables?

Power BI requires a date table for time-based calculations and analytics. You can use the built-in date table or create a custom one using DAX.

 

25. What is a Power BI Workspace?

A Power BI workspace is a container for datasets, reports, and dashboards where users can collaborate and share resources in the Power BI Service.

 

26. What is the Power BI API?

The Power BI API allows developers to interact programmatically with Power BI, enabling them to automate tasks such as embedding reports, managing datasets, or accessing user data.

 

27. What is a Power BI Dataset?

A dataset is a collection of data that is used to build reports and dashboards. It can be created from different data sources like databases, Excel files, or web services.

 

28. What is the difference between a Bar chart and a Column chart?

  • Bar Chart: Displays data in horizontal bars. Used when comparing categories with longer labels.
  • Column Chart: Displays data in vertical bars. Typically used for time-based data.
 

29. What is Power BI Integration with Excel?

Power BI integrates with Excel to allow users to publish workbooks, use Excel formulas in Power BI, and import Excel data directly into Power BI for visualization.

 

30. What is a KPI in Power BI?

A Key Performance Indicator (KPI) in Power BI is a visual that measures progress toward a business goal using a target value and an actual value.

 

31. How do you schedule data refresh in Power BI?

In the Power BI Service, you can schedule automatic data refreshes for datasets by defining the refresh frequency and time.

 

32. What is Power BI Service vs. Power BI Desktop?

  • Power BI Desktop is a free, standalone application used for report creation and modeling.
  • Power BI Service is a cloud platform used for publishing, sharing, and collaborating on Power BI reports.
 

33. What is the difference between a table and a matrix in Power BI?

  • Table: Displays data in rows and columns without any hierarchies.
  • Matrix: Displays data in a grid with row and column hierarchies, allowing for multiple levels of data aggregation.
 

34. How do you combine data from multiple sources in Power BI?

Power BI allows data integration through the Power Query Editor, where you can merge or append tables from different sources.

 

35. What are the different types of Power BI Licenses?

  • Power BI Free: Basic features for individual use.
  • Power BI Pro: Includes sharing, collaboration, and access to advanced features.
  • Power BI Premium: Provides advanced features like larger datasets, dedicated cloud resources, and enhanced performance.
 

36. What is the Power BI Paginated Report?

Paginated reports are highly formatted, printable reports that can span multiple pages, ideal for printing invoices, statements, or reports requiring exact formatting.

 

37. What is the difference between “Import” and “DirectQuery” mode?

In Import Mode, data is loaded into Power BI and stored in memory, allowing for faster query performance. In DirectQuery Mode, data is queried live from the source without storing it in Power BI.

 

38. How do you handle missing or incomplete data in Power BI?

You can handle missing data using Power Query to fill missing values, remove incomplete rows, or replace nulls with default values during data transformation.

 

39. What are Power BI Gateways used for?

Power BI Gateways are used to connect on-premises data sources (e.g., SQL Server, Excel files) to the Power BI Service for real-time or scheduled data refresh.

 

40. What is Power BI Embedded?

Power BI Embedded is a service that allows you to embed interactive Power BI reports and dashboards into your applications or websites for a seamless user experience.

 

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