Power BI Interview Questions

Power BI Interview Questions For Freshers

1. What is the full name of Power BI?

Power BI provides cloud-based BI (business intelligence) services, known as "Power BI Services'', as well as a desktop-based interface called "Power BI Desktop." It provides data repository capabilities, including data editing, data acquisition(discovery), and interactive dashboards.

2. What is Power BI?

Power BI is a cloud-based data-sharing site. Once you have improved reports using Power Query, Power Pivot, and Power View, you can share your information with colleagues. This is where Power BI comes into play. Power BI, technically a part of SharePoint online, allows you to upload Excel workbooks to the cloud and share them with a select group of colleagues. Not only that, but your colleagues can share your reports to use filters and highlight data. Power BI is an easy way to share your analytics and data from Microsoft Clouds.

3. What is a Power BI desktop?

Power BI Desktop is a free desktop application that can be installed on your computer. To access Power BI features, visualize data, or model to create reports, you can download the desktop version of Power BI. With the desktop version, you can extract data from a variety of data sources, modify it, create visuals or reports, and share it using power bi services.

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

Power BI has different types of views, namely:

• Data Views: Selecting, testing, and viewing data tables in a data set. In contrast, the query editor looks at the data after it is assigned to the model by considering the data.
   
• Model view: This view shows all the tables and their complex relationships. With this, you can break these complex models into simplified drawings or set the properties at once.
   
• Report view: It shows tables in an interactive format for easy data analysis. You can create n-number of reports, provide visuals, compile, or use any such function. 

5. Why should we use Power BI?

Power BI provides an easy way for everyone, including non-professionals, to connect, modify, and visualize their raw business data from a variety of sources and make it essential data that makes it easy to make wise business decisions.

6. How does Power BI work?

The main purpose of Power BI is to increase business growth by combining information more efficiently. It brings your company's data forward in a seamless, transparent way. Staff and team members come forward systematically by accessing the same information translated into simplified reports, charts, diagrams, and more. Power BI Works effectively by improving your operational efficiency.

7. What is row-level security?

Row-level security, based on filters, restricts the data that a user may see and access. To set up row-level security, users may define rules and roles in Power BI Desktop and upload them to Power BI Service.

8. What do you understand about Power BI custom visuals?

At PowerBI, you can create your visuals from the custom visual library. A development project should be created and test the visibility of the PowerBI service. When visualization is customized, it is tested and checked before posting. After testing, visualization is saved in .pbiviz file format before sharing. But you need to be a PowerBI Pro user to customize it.

9. What do you understand by Power Query?

Power Query is a business intelligence tool designed for Excel by Microsoft. Power Query lets you import data from a variety of data sources and will enable you to clean, modify and resize your data according to needs. Power Query lets you write your query once and use it by simple refresh.

10. What is DAX?

DAX stands for Data Analysis Expressions. A set of functions, operators, and constants is used in formulas to calculate and recover values. In other words, it helps you create new information from the data you already have.

11. What is self-help BI?

SSBI is an acronym for Self-Service Business Intelligence and is a breakthrough in business intelligence. SSBI has empowered many business professionals with no technical or coding background to use Power BI and generate reports and draw predictions successfully. Even non-technical users can create these dashboards to help their businesses make informed decisions. 

12. What are the different data types of DAX?

The types of Dax data are:- 

1) Numeric

2) Boolean

3) DateTime 

4) String and 

5) Decimal

13. What parts are included in Microsoft's Self-Service Business Intelligence Solutions?

Microsoft Self-Service BI is divided into two parts:

• Excel BI Toolkit: This allows users to build interactive reports by importing data from various sources and modelling data as needed.
   
• Power BI: It is an online service that allows users to share interactive reports and queries developed using the Excel BI Toolkit.

14. Differentiate briefly between Power BI Pro and Power BI?

Power BI provides a variety of capabilities to assist you in getting started in an entirely new manner of looking for data. On the other hand, Power BI Pro has capabilities like data scheduling, live data sources, storage capacity, comprehensive interactivity, and much more.

15. What is bi-directional cross-filtering?

Bidirectional cross-filtering allows data modellers to choose how their Power BI Desktop filters flow for data by leveraging table connections. The filter context is sent to a second related table on the other side of any given table relationship. This approach assists data modellers in resolving the many-to-many issue without the need for complex DAX calculations. To summarise, bidirectional cross-filtering makes data modellers' jobs simpler.

Power BI Interview Questions For Intermediate Level

16. Explain the three fundamental concepts of DAX?

Below are the fundamental concepts of Power BI:

• Syntax: This is how the formula is written—the pieces that make it up. Functions such as SUM are included in the Syntax (used when you want to add figures). If the Syntax is incorrect, you will receive an error notice.
   
• Functions: These formulae, like Excel functions, employ specific values (also known as arguments) in a precise sequence to execute a computation. Date/time, time intelligence, information, logical, mathematical, statistical, text, parent/child, and other functions are available.
   
• Context: There are two kinds of context: row and filter contexts. When a formula contains a function that applies filters to identify a single row in a table, row context comes into play. The filter context is used when one or more filters are used in a calculation to determine a result or value.

17.  What is the difference between Distinct() and Values() in DAX?

We use the Distinct() and Values() methods to return the values to a worksheet column or cell. The distinction is that the Values() method returns both blank values and unique values, but the Distinct() function only returns unique values.

18. What is SSBI?

SSBI is an abbreviation for Self-Service Business Intelligence. It is also known as data analytics access because it enables business users to partition, clean, and evaluate data. SSBI has made it simple for end-users to access their data and generate various graphics to gain valuable business insights. Anyone with a rudimentary understanding of data may create reports to create intuitive and shared dashboards.

19. What are responsive slicers in Power BI?

A developer may scale a responsive slicer to various widths and shapes on a Power BI final report page, and the data gathered in the container will be reorganised to find a match. When a visual report grows too tiny to be effective, a symbol representing the visual replaces it, freeing up space on the report page.

20. What are the KPIs in Power BI?

KPIs are Key Success Indicators that measure the performance of a company in certain areas by analyzing quantifiable objectives and values. A KPI has a base value or measure compared to goal values. It contains a performance comparison with the aim. With their graphical portrayal, KPIs can assist you in evaluating analysis performance. As a result, KPIs will reveal whether or not your objectives have been fulfilled.

21. State the advantages of the Direct query method?

Answer 15) The following are the benefits of using the Direct inquiry method:

• The Direct Query Method allows users to create large data sets of data visualizations. However, the Power BI desktop-only enables data visualizations on smaller sets.
   
• The direct query technique has no dataset limit, and the 1GB dataset restriction does not apply to this approach.

22. Explain how to use Power BI's responsive slicer.

The developer can resize and shape the responsive slicer on the Power BI final report page. The data collected in the container will be reorganized to achieve the same result (find the match). The graphical icon replaces the visual report when it becomes too small to be used, saving space on the report page.

23. What do you mean by M language?

M is a case-sensitive functional programming language that is utilised in Power queries. It is simple to use and similar to other programming languages.

24. What are the various connection modes in Power BI?

The three modes of connection are: 

• Import mode is the default mode in PowerBI because it is commonly used and provides rapid performance. It can aggregate data from several sources, and then save and fully load imported data on a disc while updating or querying.
   
• Direct Query mode: This is another method of importing data by querying an existing data source. We utilise DirectQuery to prevent updating the data if the data volume is too large, as it may take longer.
   
• Composite Mode: Import and Direct Query modalities are combined in Composite Mode. This option works with tables that DirectQuery doesn't. It combines the best features of the previous two modes.

25. What is SSRS? How is it different from Power BI?

SQL Service Reporting Service stands for SQL Service Reporting Service. It's a reporting platform that runs on a server. Microsoft's SQL Server suite includes SSRS. In many aspects, it is similar to Power BI, although it is a more traditional tool. SSRS is primarily used for enterprise data visualization and report generation, viewing, and sharing. It contains an integrated set of processing components and a programming interface. SSRS includes less graphical, drag-and-drop options and more programming-based tools for report creation. As a result, users must exert more significant manual effort. 

The following are some critical distinctions between Power BI and SSRS:

• SSRS requires a SQL Server licence, but Power BI is free. However, Power BI Report Server requires purchasing a Power BI Premium subscription.
   
• SSRS is server-based, whereas Power BI is cloud-based.
   
• SSRS is traditional and programming-based, whereas Power BI is more current and graphical. To prepare reports and do analyses with SSRS, manual effort and time are required.
   
• In Power BI, we may use data from the cloud. We can only use on-premise data using SSRS.
   
• Cortana has been integrated into Power BI, enabling AI-based natural language and Q&A about your data and reports. This feature is not available in SSRS.
   
• In SSRS, you must purchase a license, define requirements and scope, customize your software, deploy, develop reports in a coding interface, schedule data refreshes, etc.
   
• Power BI has a graphical interface with the drag-and-drop capability to create reports. You can work with unstructured data, use modern rendering, publish, integrate and collaborate easily across platforms.

26. What are the types of visualizations in Power BI?

A graphical depiction of data is called visualisation. Reports and dashboards can be created using visualisations. Bar charts, Column charts, Line charts, Area charts, Stacked area charts, Ribbon charts, Waterfall charts, Scatter charts, Pie charts, Donut charts, Treemap charts, Maps, Funnel charts, Gauge charts, Cards, KPI, Slicer, Table, Matrix, R script visual, Python visual, and others are examples of visualisations available in Power BI.

27. Explain paginated reports.

A paginated report is a document-style report structured from page to page. Paginated reports are saved as paged documents, which can be expanded vertically and horizontally to access all information. These reports have a fixed layout and are pixel-perfect. When printing a report from a PDF or Word file, they may be the best option. The.RDL extension is used for paginated files.

28. What is Power BI Designer?

Power BI Designer is a standalone Power BI companion application. Power Query, Power Pivot, and Power View combine into one application. Power BI Designer is a tool for working with data and creating Power BI reports and other features. The Power BI Designer can be downloaded from the Power BI website. Reports developed in Power BI Designer can later be published to the Power BI Service. 

29. Explain the transformation in Power Query Editor?

The Power Query Editor allows us to import data from various sources and change it in a variety of ways to meet our needs. 

The following are some common data transformation practices in Power Query Editor:

• Change the column data types.
   
• Columns are renamed.
   
• Change the settings.
   
• Correct any inaccuracies in the Any Column group.
   
• In Structured Column groups, working with nested data.
   
• Add custom columns, conditional columns, measurements, and other features.
   
• Run R Script tool in Power BI Query Editor, run R Queries directly.

30. Is it possible to incorporate geographic data into Power BI Reports? If so, how should you proceed?

Yes, there are various ways to map geographic data into Power BI reports. Bing Maps is integrated with Power BI, and by default, it offers the coordinates of locations on the map. This is known as geocoding because it eliminates the need for users to enter longitude and latitude data manually. In Power BI, you can utilize map charts and filled map charts to use geographic data in reports and dashboards.

Power BI Interview Questions For Experienced

31. How many active relationships can we have between two tables in the Power Pivot data model?

In a Power Pivot data model, we can have several relationships between tables. However, in the data model between two tables, there can only be one active relationship at a time. The other relationships stay inactive while one of the many relationships is active. Active relationships are depicted by a continuous line in the Power Pivot data model, while dotted lines indicate inactive relationships.

32. Difference Between New Measure and New column?

A new column is a region in Power Bi where physical data is saved when logic is applied, whereas a measure is where computations based on dimensions are conducted on the fly. In contrast to Column, Action will not retain any physical data.

33. Explain the building blocks of Microsoft Power BI.

Power BI's key building blocks are as follows:

• Visualizations: The practice of creating charts and graphs to illustrate insights from corporate data is known as visualization.
   
• Datasets: A dataset is a collection of data used to produce a display, such as a sales column. A dataset may be aggregated and filtered from several sources using built-in data plugins.
   
• Reports: The report stage is the last. A collection of visualizations on one or more pages may be found here. A final report, for example, may include charts and maps.
   
• Dashboards: A Power BI dashboard enables you to share a single visualization with colleagues and clients for them to see your final dashboard.
   
• Tiles: A tile is a standalone visualization on your final dashboard or one of your final report's charts.

34. List out some drawbacks of using Power BI.

The following are some of the limitations of Power BI:

• Power BI does not accept files bigger than 1 GB in size and does not blend imported and real-time data.
   
• Few data sources provide real-time access to Power BI reports and dashboards.
   
• It only shows dashboards and reports to people who use the same email address.
   
• Dashboard does not take or pass parameters for users, accounts, or others.

35. What are the differences between calculated columns and measures in Power BI?

Calculated columns are computed for each row in a table and stored in the model. It helps to increase its size. We can use calculated columns for row-level calculations. On the other hand, measures are calculated on the fly based on user interactions. They don't increase model size. We can use measures for aggregations.

36. How do we optimize Power BI reports for better performance?

We can optimize Power BI reports for better performance by:

• Reducing the amount of data imported
• Using incremental refresh
• Avoiding unnecessary visuals
• Using bookmarks for complex reports
• Optimizing DAX queries
• Using appropriate data types
• Disabling unnecessary interactions

37. How do we use the ALLEXCEPT function in DAX?

The ALLEXCEPT function in DAX returns all the rows in a table except for those that are affected by specific column filters. It's useful when you want to keep filters on specific columns while ignoring filters on other columns. For example:

Total Sales = CALCULATE(SUM(Sales[SalesAmount]), ALLEXCEPT(Sales, Sales[ProductCategory]))

In this example, the ALLEXCEPT function removes all filters except those on the ProductCategory column.

38. How can we implement dynamic row-level security in Power BI?

We can implement dynamic row-level security in Power BI by the following steps:

1. We can create a security table that maps users to allowed data
2. Then we have to establish a relationship between the security table and your fact/dimension tables
3. Then we can create a DAX measure that uses the USERNAME() function to filter data
4. Then we can apply this measure as a filter on your fact table
5. Then create roles in Power BI Desktop and assign the DAX expression
6. Then in the Power BI Service, assign users to the appropriate roles

This allows for scalable security that doesn't require manual updates to roles as data changes.

39. How can we implement user-specific data access in Power BI?

We can implement user-specific data access using Row-Level Security (RLS) in Power BI:

• Define Security Roles: Create roles in the Power BI Desktop with DAX filters that define what data is accessible to users in each role.
• Map Users to Roles: In Power BI Service, assign users to these roles. When users access the report, they will only see data filtered according to the role they are assigned.

40. How do we handle many-to-many relationships in Power BI?

We can handle many-to-many relationships in Power BI by several methods:

1. We can use bi-directional cross-filtering: Enable bi-directional filtering on the relationship, but be cautious of ambiguity in complex models
2. We can create a bridge table: Introduce an intermediary table that creates two one-to-many relationships
3. We can use DAX measures: Write measures that handle the many-to-many logic, often using CROSSJOIN or INTERSECT functions
4. We can use composite models: Combine DirectQuery and Import mode to handle complex relationships

41. How do we handle large datasets in Power BI?

We can handle large datasets in Power BI by:

• Using Aggregations: Create aggregated tables to reduce the amount of data processed.
• Incremental Refresh: Implement incremental refresh to only update new data, reducing the load on Power BI.
• Data Model Optimization: Simplify the data model by removing unnecessary columns and tables, and using appropriate data types.
• DirectQuery Mode: Use DirectQuery mode to query large datasets directly from the source without importing all data into Power BI.

42. How can we optimize DAX queries for better performance?

We can optimize DAX queries for better performance by:

1. Using variables to store and reuse complex calculations
2. Avoiding unnecessary CALCULATE functions
3. Using SUMMARIZECOLUMNS instead of SUMMARIZE for better performance
4. Prefer using relationships over RELATED function
5. Using iterators (SUMX, AVERAGEX) judiciously
6. Avoid using FILTER as a filter argument in CALCULATE
7. Using time intelligence functions instead of complex date logic
8. Minimizing the use of DISTINCTCOUNT for large datasets
9. Using DAX Studio to analyze and optimize queries

43. How do we use the RANKX function in Power BI?

The RANKX function in DAX is used to rank items in a table based on the value of an expression. For example, to rank products by total sales:

Product Rank = RANKX(ALL(Sales[Product]), SUM(Sales[SalesAmount]), , DESC, Dense)

44. Explain the concept of datamart in Power BI.

A datamart in Power BI is a Power BI Dataset created directly in the Power BI service without using Power BI Desktop. Key aspects include:

1. It allows for no-code data transformation and modeling in the cloud
2. Supports both import and DirectQuery connections
3. Can be shared and reused across multiple reports
4. Supports incremental refresh and scheduled refresh

45. What are the benefits of using Power BI Dataflows?

There are several benefits of Power BI Dataflows:

• Reusability: Dataflows can be reused across multiple reports and datasets, reducing redundancy.
• Data Consistency: Centralized data preparation ensures that all reports use consistent data transformations.
• ETL Capabilities: Dataflows provide powerful ETL (Extract, Transform, Load) capabilities using Power Query in the cloud.
• Large Data Handling: Dataflows can handle large datasets and complex transformations that might be challenging to manage within individual reports.

46. Explain the concept of query folding in Power BI.

Query folding is the process where Power Query pushes data transformation steps back to the source database. This is crucial for performance, especially with large datasets. When query folding occurs, operations like filtering and aggregations happen at the source, reducing the amount of data transferred.

47. Explain the concept of bi-directional relationships in Power BI.

Bi-directional relationships allow filters to propagate in both directions between tables. While powerful, they can lead to ambiguity in complex models and should be used cautiously. They're useful for many-to-many relationships or when you need to filter a "lookup" table based on a fact table.

48. Explain the concept of drill-through in Power BI.

Drill-through allows users to navigate from one report page to a more detailed page, carrying over the context of the selected data point. It's set up by configuring a target page to accept drill-through and adding drill-through buttons or right-click options on source visuals.

49. How do we handle time intelligence calculations in Power BI?

We can handle time intelligence calculations in Power BI using DAX time intelligence functions. These include SAMEPERIODLASTYEAR, TOTALYTD, DATEADD, etc. A date table is usually required for these functions to work correctly.

50. How do we implement cascading filters in Power BI?

We can implement cascading filters in Power BI by:

1. Creating the necessary relationships between tables
2. Using the 'Edit interactions' feature to control how filters propagate
3. Potentially using DAX measures to further refine filter behavior

Power BI MCQs

1. Which of the following is not a core component of Power BI?

a) Power BI Desktop b) Power BI Service c) Power BI Mobile d) Power BI Server

Answer: d) Power BI Server

2. What is the primary language used for creating measures in Power BI?

a) SQL b) DAX c) M d) Python

Answer: b) DAX

3. Which data connectivity mode does not store data in Power BI?

a) Import b) DirectQuery c) Live Connection d) Both b and c

Answer: d) Both b and c

4. What is the maximum size limit for a dataset in Power BI Pro?

a) 100 MB b) 1 GB c) 10 GB d) Unlimited

Answer: b) 1 GB

5. Which of the following is not a valid data source in Power BI?

a) Excel b) SQL Server c) SharePoint d) Power BI does not have data source limitations

Answer: d) Power BI does not have data source limitations

6. What is the default aggregation for numerical columns in Power BI?

a) Sum b) Average c) Count d) None

Answer: a) Sum

7. Which of the following is not a type of relationship cardinality in Power BI?

a) One-to-One b) One-to-Many c) Many-to-Many d) Few-to-Many

Answer: d) Few-to-Many

8. What is the purpose of the CALCULATE function in DAX?

a) To perform arithmetic calculations b) To modify the filter context c) To concatenate strings d) To create new tables

Answer: b) To modify the filter context

9. Which of the following is not a valid chart type in Power BI?

a) Treemap b) Funnel c) Radar d) Pie

Answer: c) Radar (as of my last update, but custom visuals may provide this)

10. What is the maximum number of rows that can be displayed in a single Power BI table visual?

a) 100 b) 1,000 c) 10,000 d) 100,000

Answer: c) 10,000

Conclusion

In this article, we have discussed Power Bi Interview Questions. Power BI is a powerful business analytics tool that has become essential for data professionals. Whether you're a fresher or an experienced professional, preparing for Power BI interview questions is crucial for landing your desired role. We discussed 50 interview questions that can help you to get a new job under the Power BI domain. 

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