Top 24 Power BI Interview questions and their answers

1. What is self-service Business Intelligence?

Self service BI refers to a scenario where a user can build there own reports and get their own insights from the report, the report is not static.

2. What is Power BI data model?

Power BI converts each dataset into a relation table, these tables can be joined with other using one to one or one to many cardinalities.

3. What data sources can Power BI connect to?

Multiple sources such as SQL server, Excels, CSVs, Flat files, Web, Facebook etc.

4. What is power query/Power BI query editor?

Power Query is used to edit the data or transform the data before we actually load it to the report and start building reports on that data.

5. Difference between Direct query and Import?

Direct query: In this mode data is not stored in Power BI data model and power BI fetches data on the fly from the Data source.
Data is always updated.
Any change in Data source will affect the report.
Direct Query is only available for a subset of database platforms supported by Power BI: SQL Server, Azure SQL Database, Azure SQL Data Warehouse, Oracle, Teradata and SAP Hanna.

Import: In this mode Power BI creates a copy of data from the source and store it in Power BI data model.
You need to refresh the report in order to get the current data from the source.
Once data is stored in model, any change in data source won’t affect Power BI report unless you refresh it.
Import is available for multiple data platforms.

6. What is the difference between calculated columns and calculated measures?

Calculated Column : We create calculated columns when we need to do a row by row operation such as Difference between Sales price and Cost price.
The column created always resides in the data set and you can view the data inside using data view.

Measure: We use calculated measures when we need to find aggregate of the values such as Sum of sales or percentage of profit etc.
The measure is always calculated on the fly and cannot be see in the data view.

7. What data transformation can be performed in Power BI?

Remove duplication, Replace Values, Remove errors, Change data type, conditional columns etc.

8. What is a parameter in Power BI? Explain with an example.

Power BI parameters are the values which we use to filter out data before it enters in our report. Suppose we want to make a report just for country Australia, we will apply parameter to the country column for Australia and Power BI will just load the data of Australia and we can see data just for Australia in our report, not other countries.

9. Use case of implementing the charts like stacked bar chart, map, matrix etc.

Bar chart is usually used to represent linear data such as Sales per product.
Map is use to show geographical data such as Country, states and cities.
Matrix is used to compare values such as Sales vs Cost per Product.
Line or area chart is used to show trend such as Sales of product on monthly basis or yearly basis.

10. What are the different types of filters used in Power BI?

Visual level filter: Applies to a particular visual or chart example : Bar chart.

Page level filter : Applies to a page in the report. Say you have 8 pages in a report and you want to apply country filter for Uganda in 3rd page only, you can use country in the page level filter in the 3rd page.

Report level filter: Applies to the entire report.

11. What is a Drill down chart?

Drill down chart is used when you want to display two associated or dependent information in a single chart, say you want to view Sales for Product category and sub category in the same visual, you can use drill down chart there.

12. How can Power BI report be published ?

You can use the publish button available on the Power BI desktop to publish the report. Report can be published to your individual Workspace or a Group workspace.

13. What are content packs?

Content packs are the container of Dashboard, reports and dataset which can be used by many users. The primary feature of content pack is that if you created a report and put it in a content pack other users can see your report and make to copy of the report and make changes to their own copy of the report while your report is safe and unaltered.

14. What is Power BI workspace?

Workspace is a Group created in Power BI containing Dashboard, reports and dataset. There are two types of users in Workspace: Admin and Member, Admin can view, edit or delete the report inside the workspace whereas Members can only view the reports inside the Workspace.

15. Can data refresh be scheduled in Power BI?

Yes, We can schedule refresh in Power BI daily or Weekly and we can also assign time based on the geographical time zones.

16. What is row level security in Power BI and how it can be implemented?

Row level security is applied when you want different users to view different information from the same report, example if you want that a user from Japan should see only Japan data and users from US should see only US data then you can use Row level security to achieve that.
Row level security can be implemented by using Manges roles option in Power BI desktop, you can assign roles based on Country, department, product etc. Row level security is applied when you want different users to view different information from the same report, example if you want that a user from Japan should see only Japan data and users from US should see only US data then you can use Row level security to achieve that.
Row level security can be implemented by using Manges roles option in Power BI desktop, you can assign roles based on Country, department, product etc.

17. What is Power BI Embedded?

Power BI embedded is a feature which allows Power BI report to be attached in a Web page of a website.

18. Difference between power BI desktop and web application?

Desktop :
You cannot share the report or Dashboard.
You can write DAX (Data Analysis Expressions) Queries to create Calculated columns and measures.
Many types of Data sources available.
You can apply relationships between multiple data sources.
More features are present.

Web Application :
You can share the report and Dashboard.
You cannot write DAX queries.
Comparatively less types of data source.
You cannot apply relationships.
Less features.

19. How to manage Visual Interaction?

Visual Interaction means that we can choose which of the chart in a page will be affected by the change in the visual filters and which chart won’t.
To Manage: Click on the Edit interaction button available under format option in Power BI, then select the filter on which the interaction are to applied, then click on the stop symbol present on each chart you wish not to be interactive with the filter.

20. How to apply user defined theme?

Click on switch theme, click on import theme, then select the JSON file created by user to apply the theme. JSON file contains the codes of the theme.

21. What is power BI Apps?

Apps is just a way of collecting all relatable dashboards and reports together and sharing them with the users.
Apps are easy to find and install in the Power BI service (https://powerbi.com) and on your mobile device. After you install an app, you don’t have to remember the names of a lot of different dashboards because they’re all together in one app, in your browser or on your mobile device.

22. Difference between dataset, report and dashboard?

Dataset: It is a collection of raw information in a relation table format which is used to make the reports.

Reports: A report is a collection of multiple visuals or charts arranged in a specific manner to represent different findings and insights from data.
Dashboards: It is a collection of reports.

23. What is Usage metrics?

Usage Metrics is the report generated by Power BI to display the information about the reports which you developed and published on the Web.
Information such as Who are users viewing the report, How many users are viewing the report per day, which report is getting maximum views etc.

24. Write a DAX query to calculate top 10 products that contribute for sales in a fact table?

Sales = SUMX(TOPN(10,Table Name ,SUM(Sales(Column Name)),ASC),sales(Column Name))

Thanks and Happy Learning.

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