Power BI Interview Questions and Answers

Power BI Interview Questions For Freshers

The rising need for organizations to make decisions based on data has increased the demand for competent professionals who can use business intelligence tools such as Power BI effectively. Power BI is a strong analytics service that helps users to visualize data and share insights with their organizations. In this chapter, we are going to learn some basic questions about Power BI asked in the interview for freshers. All these questions address the most significant concepts, functionalities, and benefits of Power BI, creating an excellent ground for understanding this versatile tool.

1. What is Power BI?

Power BI is a business analytics service that provides interactive visualizations and business intelligence capabilities. It allows users to create reports and dashboards from various data sources, facilitating data-driven decision-making within organizations.

2. Why should we use Power BI?

Power BI offers several advantages, including user-friendly interfaces, robust data visualization capabilities, integration with other Microsoft products, and the ability to handle large datasets efficiently. This makes it an ideal choice for businesses looking to enhance their data analysis processes.

3. Difference between Power BI and Tableau

Both tools are used for data visualization, but Power BI is more integrated with Microsoft products, making it easier for users in Microsoft environments. Tableau offers more advanced visualization options and is often preferred for complex analytics tasks.
For further details on Microsoft-related courses including Power BI, you can explore our Microsoft Training page. 

4. Difference between Power Query and Power Pivot

Power Query is used for data extraction and transformation, allowing users to clean and shape their data before analysis. Power Pivot, on the other hand, is focused on data modeling and allows users to create relationships between different datasets.

5. What is Power BI Desktop?

Power BI Desktop is a free application that allows users to create reports and dashboards by connecting to various data sources. It provides tools for data modeling, visualization, and report design.

6. What is Power Pivot?

Power Pivot is an Excel add-in that allows users to perform powerful data analysis and create sophisticated data models. It enables users to work with large datasets efficiently using in-memory technology.

7. What is Power Query?

Power Query is a data connection technology that enables users to discover, connect, combine, and refine data across a wide variety of sources. It simplifies the process of preparing data for analysis.

8. Describe the components of Microsoft’s self-service BI solution?
   
   

Microsoft’s self-service BI solution includes components like Power BI Desktop for report creation, Power Query for data preparation, Power Pivot for modeling, and Power BI Service for sharing reports online.

9. What is self-service BI?

Self-service BI empowers end-users to access and analyze data independently without relying on IT departments. It allows users to create reports and dashboards tailored to their specific needs.

10. What is DAX?

DAX (Data Analysis Expressions) is a formula language used in Power BI for creating custom calculations in reports. It includes functions for filtering, aggregating, and manipulating data.

11. What are Filters in Power BI?

Filters in Power BI allow users to limit the data displayed in reports or visuals based on specific criteria. They can be applied at various levels: visual-level, page-level, or report-level.

12. What are Custom Visuals in Power BI?

Custom visuals are user-created visualizations that can be imported into Power BI reports. They extend the standard set of visuals available in Power BI by providing unique ways to display data.

13. What is GetData in Power BI?

GetData is a feature in Power BI that allows users to connect to various data sources such as databases, Excel files, web services, and more. It serves as the starting point for importing data into the application.

14. Mention some advantages of Power BI?

Advantages include ease of use, integration with other Microsoft tools (like Excel), real-time dashboard updates, extensive visualization options, and strong community support.

15. List out some drawbacks/limitations of using Power BI?

Limitations include restrictions on dataset size (for free versions), dependency on internet connectivity for cloud features, potential performance issues with very large datasets, and limited customization options compared to some competitors.

16.  What are some differences in data modeling between Power BI Desktop and Power Pivot for Excel?

While both tools allow for creating relationships between tables and building models, Power BI Desktop supports more advanced features like direct query connections and real-time collaboration through the cloud.

17. Name the different connectivity modes available in Power BI?

The main connectivity modes are:

1. Import Mode: Data is imported into the model.
2. DirectQuery Mode: Queries are sent directly to the source database.
3. Live Connection: A direct connection to an Analysis Services model or Azure Analysis Services.
17. What are the various types of refresh options provided in Power BI?

Refresh options include:

1. Manual Refresh: Users refresh datasets manually.
2. Scheduled Refresh: Automatic refresh at specified intervals.
3. DirectQuery: Real-time querying of live databases without needing refreshes.
18. What are the different types of data sources you can connect to in Power BI?

Users can connect to a wide range of sources including SQL Server databases, Excel files, cloud services (like Azure), web APIs, SharePoint lists, and many more.

20. What is a dashboard in Power BI?

A dashboard is a single-page interface that displays key metrics through visualizations from multiple reports. It provides a high-level overview of performance indicators at a glance.

21. Explain how relationships are defined in Power BI Desktop?

Relationships can be defined manually by specifying primary and foreign keys or automatically through the model's auto-detect feature which identifies relationships based on matching column names.

22. Can you have more than one functional relationship between two tables in a Power Pivot data model?

No, only one active relationship can exist between two tables at any time; however, multiple inactive relationships can be defined which can be activated using DAX functions like USERELATIONSHIP.

23. Can you have a table in the model which does not have any relationship with other tables?

Yes, it’s possible to have standalone tables without relationships; they can still be used within measures or calculations but won't interact with other tables' filters or context.

24. What is the CALCULATE function in DAX?

CALCULATE modifies the filter context applied to a calculation by evaluating an expression under new filter conditions specified by additional arguments.

25. How do you connect to data in Power BI?

Users connect to data by selecting "Get Data" from the Home tab in Power BI Desktop. They then choose their desired source type (e.g., Excel file or SQL database) and follow prompts to establish the connection.

26. How do you publish a report in Power BI?

Reports created in Power BI Desktop can be published directly to the Power BI Service by clicking on the "Publish" button found on the Home ribbon after signing into your account.

27. What is a calculated column in Power BI?

A calculated column adds new column values based on DAX formulas applied row by row within a table during data load or refresh processes.

28. What is a measure in Power BI?

A measure performs calculations on aggregated values dynamically based on filters applied within reports; they are recalculated based on user interactions with visuals.

29. What is a Fact Table and Dimension Table in Power BI?

A Fact Table contains quantitative data (metrics) for analysis while Dimension Tables contain descriptive attributes related to facts (like time periods or product categories).

30. What are the rules regarding Dimension Tables?

Dimension Tables should contain unique values as primary keys; they should also be denormalized where possible to optimize performance during queries.

31. How do you connect a Fact Table and a Dimension Table in Power BI?

Connections are made by establishing relationships based on common fields (keys) such as foreign keys from Fact Tables pointing back to primary keys in Dimension Tables.

32. What are the different languages used in Power BI?

The primary languages include DAX for calculations within models and M language used within queries for transforming raw data during import processes via Power Query.

33. What is the easiest method to navigate in Power BI?

The easiest navigation method involves using bookmarks for quick access between views or utilizing drill-through features within reports for detailed insights into specific metrics.

Power BI Interview Questions For Intermediate Level

As professionals go through their career, they might be expected to possess a deeper understanding of Power BI, including knowing its "inner workings" and capacity. This includes not only knowing the basic features but being aware of more advanced features, data modeling techniques, and best practices in report creation and data analysis. In the following sections, we will discuss some intermediate-level questions that have more to do with the intricacies of Power BI. These questions are aimed at assessing a candidate's ability to effectively use Power BI in a professional setting, touching on data storage, security, relationships, and performance optimization.

1. Where is data stored in Power BI?

Data in Power BI can be stored in several ways depending on the version being used. In Power BI Desktop, data is stored in an internal model using a highly optimized columnar storage format. For users of Power BI Service, datasets are stored in Microsoft Azure, allowing for cloud-based accessibility and collaboration.

2. What is row-level security?

Row-level security (RLS) in Power BI restricts data access at the row level based on user roles. This means that different users can see different data within the same report or dashboard, ensuring that sensitive information is only visible to authorized individuals.

3. Why should you apply general formatting to Power BI data?
   
   

General formatting of Power BI data enhances report readability and consistency. It facilitates stakeholders to view visualizations fast and understand the insights without any confusion caused due to different formats, thereby enhancing the overall experience of the users.

4. What are the different views available in Power BI Desktop?
   
   

Power BI Desktop offers three main views:

• Report View: For designing and building reports.
• Data View: To inspect and analyze the underlying dataset.
• Model View: For managing relationships between tables and visualizing the data model structure.
4. What are the various versions of Power BI?
   
   

There are three main versions of Power BI:

• Power BI Desktop: A free version for creating reports and dashboards.
• Power BI Pro: A paid version that allows sharing, collaboration, and more extensive features.
• Power BI Premium: Offers enhanced performance, larger storage capacities, and advanced features for enterprise-level deployments.
5. Explain the building blocks of Microsoft Power BI?
   
   

The building blocks of Microsoft Power BI include:

• Datasets: The data sources imported into Power BI.
• Reports: Collections of visuals based on datasets.
• Dashboards: Single-page summaries created from multiple reports.
• Workspaces: Collaborative environments for managing content and sharing insights among users.
6. What are the critical components of the Power BI toolkit?
   
   

The critical components of the Power BI toolkit include:

• Power Query: For data extraction and transformation.
• Power Pivot: For data modeling and creating relationships.
• DAX (Data Analysis Expressions): A formula language for calculations.
• Power BI Service: The online platform for sharing and collaboration.
7. What do you mean by the content pack?
   
   

A content pack in Power BI is a pre-packaged collection of related dashboards, reports, datasets, and Excel files that can be shared with users. Content packs can be created by organizations or sourced from third-party providers to facilitate easy access to common analytics resources.

9. Define bi-directional cross filtering?
   
   

Bi-directional cross filtering allows filters to flow both ways between related tables in a data model. This means that when a filter is applied to one table, it affects related tables as well, enabling more dynamic interactions within visualizations.

10. What are the three fundamental concepts of DAX?
    
    

The three fundamental concepts of DAX are:

• Filter Context: The set of filters applied to a calculation based on user selections or report filters.
• Row Context: The context of a single row when performing calculations across tables.
• Evaluation Context: The combination of filter context and row context that determines how DAX formulas are evaluated.
10. Why and how would you use a custom visual file?
    
    

Custom visual files can be used in Power BI to enhance visualizations beyond standard options. Users can import these visuals from external sources or create their own using tools like TypeScript or D3.js to meet specific analytical needs or provide unique insights.

12. What are some familiar sources for data in the Get Data menu in Power BI?
    
    

Common sources available in the Get Data menu include:

• Excel files
• SQL Server databases
• SharePoint lists
• Online services (like Google Analytics)
• Web APIs
12. What are the categories of data types?
    
    

Data types in Power BI include:

• Text: For string values.
• Number: For integer or decimal values.
• Boolean: For true/false values.
• Date/Time: For date and time values.
13. Name some commonly used tasks in the Query Editor?
    
    

Common tasks performed in Query Editor include:

• Data transformation (e.g., merging, appending queries).
• Cleaning data (e.g., removing duplicates, filtering rows).
• Changing data types for columns.
• Creating calculated columns based on existing data.
14. What do you mean by grouping?
    
    

Grouping in Power BI refers to consolidating rows based on shared attributes to summarize data. This allows users to aggregate values (like sums or averages) for categories within a dataset, making it easier to analyze trends and patterns.

16. Explain responsive slicers in Power BI?
    
    

Responsive slicers adjust their size and layout dynamically based on the available space within a report. This feature enhances user interaction by ensuring that slicers remain accessible and visually appealing across different screen sizes and devices.

17. What is query folding in Power BI?
    
    

Query folding refers to the ability of Power Query to push transformations back to the source database rather than processing them within Power BI itself. This optimizes performance by leveraging the database's capabilities for handling large datasets efficiently.

18. What is "M language"?
    
    

M language is a functional programming language used in Power Query for data manipulation and transformation tasks. It allows users to write complex queries for importing, shaping, and cleaning data before loading it into Power BI.

19. Can you give an example of a DAX function?
    
    

An example of a DAX function is SUM(), which calculates the total sum of a column's values. For instance, Total Sales = SUM(Sales[SalesAmount]) computes the total sales amount from the Sales table.

20. Explain the difference between a calculated column and a measure?
    
    

A calculated column is computed during data load and stored within the model as part of the table; it evaluates row-by-row. A measure calculates results dynamically based on filters applied during report interactions, providing aggregated results across rows.

21. Which gives better performance: Calculated columns or measures?
    
    

Generally, measures provide better performance compared to calculated columns because they are computed at query time rather than during data load. Measures also reduce memory usage since they do not increase model size like calculated columns do.

22. What are the different types of relationships in Power BI?
    
    

The different types of relationships include:

• One-to-One (1:1): Each record in one table corresponds to one record in another table.
• One-to-Many (1:N): One record from one table relates to multiple records in another table.
• Many-to-Many (N:N): Records from both tables can relate to multiple records from each other.
22. How do you create relationships in Power BI?
    
    

Relationships can be created by navigating to the Model view in Power BI Desktop and dragging lines between fields that represent keys in related tables. Alternatively, users can define relationships through the "Manage Relationships" dialog box by specifying primary and foreign keys.

24. Can you have a table in the model which does not have any relationship with other tables?
    
    

Yes, it is possible to have standalone tables without relationships with other tables; these tables can still be used within measures or calculations but won't interact with other tables' filters or context.

25. What are the different types of joins in Power BI and their uses?
    
    

Power BI supports several join types:

• Inner Join: Returns only matching rows from both tables.
• Left Join: Returns all rows from the left table and matching rows from the right table; non-matching rows will have nulls.
• Right Join: Returns all rows from the right table with matching rows from the left; non-matching rows will have nulls.
• Full Outer Join: Returns all rows when there is a match in either left or right table records.
25. What are the major differences between Power BI and Excel?
    
    

Key differences include:

• Data Visualization: Power BI offers advanced visualization options compared to Excel's basic charts.
• Data Capacity: Power BI handles larger datasets more efficiently than Excel's limitations.
• Collaboration: Power BI facilitates real-time collaboration through its cloud service while Excel primarily focuses on individual use unless integrated with SharePoint or similar tools.
26. Explain the difference between Power BI Desktop and Power BI Service?
    
    

Power BI Desktop is a desktop application used for creating reports and dashboards offline, while Power BI Service is an online platform that enables sharing, collaboration, and real-time updates of reports created with Desktop. The Service also supports cloud storage options.

28. What is a Power BI workspace?
    
    

A workspace in Power BI is a collaborative environment where users can create, manage, and share reports, dashboards, datasets, and other resources with team members or stakeholders within an organization.

29. How do you optimize Power BI reports for performance?
    
    

To optimize reports for performance:

• Limit dataset size by removing unnecessary columns or rows.
• Use measures instead of calculated columns where possible.
• Minimize visuals on each report page to reduce rendering time.
• Implement query folding where applicable when using DirectQuery mode.
29. What is the difference between a slicer and a filter in Power BI?
    
    

A slicer is a visual element that allows users to select values directly on reports for filtering data interactively; it provides an intuitive way to segment information visually. Filters apply more broadly at visual-level, page-level, or report-level without direct interaction through visuals.

31. Explain the difference between SUM and SUMX in DAX?
    
    

SUM() calculates total values directly from a specified column across all rows without any additional context. In contrast, SUMX() evaluates an expression over a table row-by-row before summing up results; it's useful when calculations involve multiple columns or require context-specific evaluations.

32. What is the purpose of time intelligence functions in Power BI?
    
    

Time intelligence functions allow users to perform calculations based on dates effectively—enabling comparisons over time periods such as year-to-date totals or previous year comparisons easily within DAX formulas.

33. What is a Semantic Model?
    
    

A Semantic Model defines how data elements relate within databases or datasets while providing business logic through measures, hierarchies, metadata definitions etc., facilitating easier understanding and analysis by end-users without needing deep technical knowledge about underlying structures.

Power BI Interview Questions for Experienced

As professionals move into higher career brackets, it will be expected to have in-depth knowledge about the Power BI capabilities and the nuances of the Power BI functionalities available. That should not only get them comfortable to use the application but also skilled in the areas of best data modeling, optimizing performance, and report design. In this section, we will look at a set of questions targeting experienced candidates with complex scenarios and deeper insights into Power BI. These questions are designed to test the candidate's expertise and practical knowledge, pointing out their capability to use Power BI effectively in a professional environment.

1. What are the major differences between visual-level, page-level, and report-level filters in Power BI?
• Visual-Level Filters: These filters apply to individual visualizations, allowing users to control what data is displayed in specific charts or graphs. They do not affect other visuals on the report page.
• Page-Level Filters: These filters affect all visuals on a single report page, providing a cohesive view of data that meets specific criteria across multiple visuals.
• Report-Level Filters: These filters apply to all pages within a report, ensuring that the same filter criteria are consistently applied throughout the entire report.
2. List the most common techniques for data shaping?

Common data shaping techniques include:

• Filtering Rows: Removing unnecessary data based on specific criteria.
• Changing Data Types: Ensuring each column has the correct data type for analysis.
• Merging Queries: Combining data from multiple sources into a single dataset.
• Grouping Data: Aggregating data based on shared attributes to summarize information.
2. How is the Schedule Refresh feature designed to work?
   
   

The Schedule Refresh feature allows users to automate the updating of datasets in Power BI Service at specified intervals. Users can set up refresh schedules based on their needs (e.g., daily, weekly) to ensure that reports and dashboards reflect the most current data without manual intervention.

4. What information is needed to create a map in Power Map?
   
   

To create a map in Power Map, you need:

• Geographic data (like addresses, cities, or coordinates) to plot locations accurately.
• Data fields that represent values or metrics to visualize (e.g., sales figures).
• A clear understanding of how you want to represent this data visually (e.g., heat maps or clustered points).
4. Which in-memory analytics engine does Power Pivot use?
   
   

Power Pivot uses the VertiPaq engine, which is an in-memory analytics engine designed for fast data compression and retrieval. This engine enables efficient querying and processing of large datasets within Excel and Power BI.

6. Mention important components of SSAS?
   
   

Important components of SQL Server Analysis Services (SSAS) include:

• Data Models: Structures that define how data is organized and related.
• Cubes: Multi-dimensional structures that allow for efficient querying and analysis of data.
• Dimensions and Measures: Dimensions provide context (e.g., time, geography), while measures are quantitative values used for analysis (e.g., sales amounts).
• Data Mining: Tools for discovering patterns and insights from large datasets.
6. What are the three fundamental concepts of DAX?
   
   

The three fundamental concepts of DAX (Data Analysis Expressions) are:

• Filter Context: The set of filters applied to a calculation based on user interactions or report filters.
• Row Context: The context of a single row when performing calculations across tables.
• Evaluation Context: The combination of filter context and row context that determines how DAX formulas are evaluated.
7. Name the variety of Power BI Formats?
   
   

Power BI supports various formats including:

• PBIX files: Used for Power BI Desktop reports.
• PBIT files: Template files for reports without data.
• Power BI Service dashboards and reports, which are stored online for sharing and collaboration.
8. What are the different stages in the working of Power BI?
   
   

The different stages include:

• Data Preparation: Importing and transforming raw data using Power Query.
• Data Modeling: Creating relationships between datasets using Power Pivot.
• Report Creation: Designing reports with visuals in Power BI Desktop.
• Publishing and Sharing: Uploading reports to Power BI Service for collaboration and distribution.
9. Which professionals use Power BI the most?
   
   

Professionals who commonly use Power BI include:

• Business analysts who need to visualize data insights.
• Power BI Data analysts (Data Analysts) responsible for reporting and dashboard creation.
• IT professionals who manage data governance and security.
• Executives seeking high-level metrics for decision-making.
10. What is the advanced editor?
    
    

The Advanced Editor in Power BI allows users to write or modify M code directly for queries. This feature provides greater control over data transformations beyond what is available through the standard UI, enabling complex query definitions.

12. What gateways does Power BI have and why should you use them?
    
    

Power BI offers two types of gateways:

• Personal Gateway: For individual users to refresh on-premises datasets without needing IT support; ideal for personal use cases.
• Enterprise Gateway: For organizations needing centralized management of scheduled refreshes across multiple users; it supports larger-scale deployments with enhanced security.
12. Mention some applications of Power BI?
    
    

Applications of Power BI include:

• Sales performance analysis dashboards.
• Financial reporting and forecasting tools.
• Marketing campaign performance tracking.
• Operational reporting for supply chain management.
13. How can you depict a story in Power BI?
    
    

You can depict a story in Power BI by using a combination of visuals that guide viewers through insights step-by-step. This includes using narrative text boxes, sequential visuals, and interactive elements like drill-throughs to engage users with the data effectively.

15. What are KPIs in Power BI?
    
    

Key Performance Indicators (KPIs) in Power BI are metrics used to evaluate success against defined objectives. They provide visual representations of performance against targets, often displayed as colored indicators (green, yellow, red) based on thresholds set by users.

16. What is a Slicer?
    
    

A slicer is a visual element in Power BI that allows users to filter data interactively within reports. It provides an intuitive way to segment information by selecting specific categories or values directly from the report interface.

17. Explain Power BI Designer?
    
    

Power BI Designer is a free desktop application that consolidates essential tools like Power Query, Power Pivot, and visualizations into one interface. It allows users to build reports offline before uploading them to the Power BI Service for sharing.

18. How do you reshape data in Power BI?
    
    

Data can be reshaped in Power BI using features within Power Query such as filtering rows, changing column types, merging queries, pivoting/unpivoting columns, or grouping data based on specific attributes.

19. What is the difference between a star schema and a snowflake schema in data modeling?
    
    

A star schema involves a central fact table directly connected to dimension tables, making queries easier but likely redundant. On the other hand, a snowflake schema normalizes dimension tables into multiple related tables that tend to have reduced redundancy but make queries more complex.

20. What is the USERELATIONSHIP function in DAX?
    
    

The USERELATIONSHIP function in DAX allows users to specify which relationship between two tables should be used when calculating measures. This is particularly useful when there are multiple relationships between two tables but only one can be active at any time.

21. How do you handle many-to-many relationships in Power BI?
    
    

Many-to-many relationships can be handled by creating bridge tables that connect two tables indirectly. This involves creating an intermediary table that contains unique values from both related tables, allowing for effective filtering and aggregation.

22. What is the difference between VALUES and DISTINCT in DAX?
    
    

Both VALUES and DISTINCT return unique values from a column; however, VALUES also returns blank values if they exist within the column while DISTINCT does not. VALUES is often used when needing context-aware results based on filter context.

23. What is the purpose of the CROSSFILTER function in DAX?
    
    

The CROSSFILTER function changes how filters propagate between two related tables during calculations. It allows users to specify whether filtering should be unidirectional or bidirectional when evaluating measures involving relationships.

24. How do you manage dynamic data updates in Power BI?
    
    

Dynamic data updates can be managed through scheduled refreshes set up in the Power BI Service or by using DirectQuery mode which allows real-time querying against live databases without needing manual refreshes.

25. Explain Row Context and Filter Context?
    
    

Row context refers to the current row being evaluated during calculations within DAX formulas; it’s automatically applied when iterating over rows. Filter context refers to filters applied from slicers or other visuals that affect what rows are considered during calculations.

26. What is the difference between ‘Append Query’ and ‘Merge Query’ in Power BI?
    
    

'Append Query' combines rows from two or more tables into one table vertically (stacking), while 'Merge Query' combines columns from two tables horizontally based on matching keys (joining). Append is used when datasets have similar structures; merge is used when datasets contain related information.

27. How do you compare last year’s numbers to this year’s numbers in Power BI?
    
    

You can compare last year’s numbers to this year’s numbers by creating measures using DAX functions like SAMEPERIODLASTYEAR() or PREVIOUSYEAR() along with time intelligence functions that allow easy year-over-year analysis within your reports.

28. What is the purpose of the ‘What If’ parameter in Power BI?
    
    

The ‘What If’ parameter allows users to create scenarios by changing input values dynamically within reports. This feature enables stakeholders to visualize potential outcomes based on varying assumptions or conditions without altering underlying datasets directly.

29. What is a Power BI App?
    
    

A Power BI App is a packaged collection of related dashboards and reports published together for easier distribution among users within an organization. Apps provide a streamlined way for teams to access relevant insights without navigating through individual reports.

30. What are dataflows in Power BI and some of their benefits?
    
    

Dataflows allow users to create reusable ETL processes within the cloud-based environment of Power BI Service. Benefits include centralized management of transformation logic, improved collaboration across teams, and streamlined access to cleaned datasets across multiple reports.

31. What is Fabric?
    
    

Fabric refers to Microsoft's unified analytics platform designed for seamless integration across various analytics services including Azure Data Factory, Azure Synapse Analytics, and others. It aims to simplify workflows by providing an end-to-end solution for managing analytics processes.

32. What is OneLake Data Hub?
    
    

OneLake Data Hub is the centralized repository, in fact, designed for vast amounts of structured and unstructured data, spread across a variety of services, within a single, cohesive ecosystem that offers easier access and integration between multiple analytics tools and provides robust governance features.