Top 30 Power BI Interview Questions with Hints

Power BI is one of the most sought-after skills in the data analytics domain, and if you're preparing for an interview, it's crucial to be well-versed in both the fundamentals and advanced aspects of this powerful tool. At PowerBIXperts, we've compiled a comprehensive list of the top 100 interview questions along with concise hints to help you ace your next Power BI interview.

Whether you're an aspiring data analyst, a seasoned business intelligence professional, or simply looking to upskill, this guide will give you the edge you need.

Section 1: Basics of Power BI

1. What is Power BI?

   • Hint: A suite of business analytics tools to visualize data and share insights.

2. What are the key components of Power BI?

   • Hint: Power BI Desktop, Service, Mobile Apps, Gateway, Embedded, and Report Server.

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

   • Hint: Desktop is for creating reports; Service is for sharing and collaboration.

4. What is a Power BI Dashboard?

   • Hint: A single-page visualization that consolidates multiple reports.

5. How does Power BI differ from Excel?

   • Hint: Advanced visualization, real-time data access, and data transformation capabilities.

Section 2: Data Sources and Connectivity

1. What data sources can Power BI connect to?

   • Hint: Databases, Excel, APIs, Cloud services, etc.

2. What is Power Query in Power BI?

   • Hint: A data connection technology for transforming and preparing data.

3. Explain DirectQuery vs. Import Mode.

   • Hint: DirectQuery connects live to the data source; Import pulls data into Power BI.

4. What are the limitations of DirectQuery?

   • Hint: Limited transformations, no built-in DAX functions, and performance constraints.

5. How do you refresh data in Power BI?

   • Hint: Manual refresh in Power BI Desktop, scheduled refresh in Power BI Service.

Section 3: Data Modeling

1. What is data modeling in Power BI?

   • Hint: Organizing data into tables, relationships, and calculations for analysis.

2. How do you create relationships between tables in Power BI?

   • Hint: Use the Relationships view and drag fields to create joins.

3. What is a Star Schema?

   • Hint: A data model with fact tables and dimension tables arranged like a star.

4. Explain the purpose of calculated columns and measures.

   • Hint: Columns add new data; measures are for calculations on data.

5. What is a calculated table in Power BI?

   • Hint: A table created using DAX, not directly from the data source.

Section 4: DAX (Data Analysis Expressions)

1. What is DAX in Power BI?

   • Hint: A formula language for calculations and data analysis.

2. Explain the difference between a calculated column and a measure.

   • Hint: Calculated columns are stored in the data model; measures are calculated on the fly.

3. How does the CALCULATE function work in DAX?

   • Hint: Changes the context in which data is evaluated.

4. What is the purpose of the RELATED function?

   • Hint: Retrieves a related value from another table.

5. Explain the concept of context in DAX.

   • Hint: Two types—Row context and Filter context, affecting how DAX formulas are evaluated.

Section 5: Visualization

1. What types of visuals are available in Power BI?

   • Hint: Bar charts, line charts, pie charts, tables, matrices, maps, etc.

2. How do you use custom visuals in Power BI?

   • Hint: Import them from the Microsoft AppSource or as .pbiviz files.

3. What is a slicer in Power BI?

   • Hint: A visual filter to slice data by specific criteria.

4. How do you create a calculated field for visuals in Power BI?

   • Hint: Use DAX to create measures or calculated columns.

5. Explain the use of bookmarks in Power BI.

   • Hint: Save specific states of a report page for easy navigation or storytelling.

Section 6: Advanced Topics

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

   • Hint: Restricts data access for users based on roles.

2. How can you optimize the performance of a Power BI report?

   • Hint: Use aggregations, avoid complex visuals, and minimize data load.

3. What is Power BI Embedded?

   • Hint: Embedding Power BI reports and dashboards into applications.

4. Explain the concept of composite models.

   • Hint: Combines data from different sources (e.g., DirectQuery and Import) in one report.

5. What are incremental refreshes in Power BI?

   • Hint: Refreshes only the data that has changed since the last refresh.

Section 7: Power BI Service and Collaboration

1. How do you share reports and dashboards in Power BI?

   • Hint: Through workspaces, apps, or direct sharing links.

2. What is the Power BI Gateway, and why is it needed?

   • Hint: Bridges on-premises data sources with Power BI Service for live data access.

3. Explain the use of Power BI workspaces.

   • Hint: Collaborative spaces for teams to work on reports and dashboards.

4. What are Power BI apps?

   • Hint: Packaged reports and dashboards for easier distribution and consumption.

5. How do you manage permissions in Power BI?

   • Hint: Assign roles and access levels in workspaces and content sharing settings.