Power BI Interview Questions and Answers
Microsoft Power BI is popular for a reason. This self-service business intelligence cloud service not only is highly rated—it’s free. PCMag.com reviewer Pam Baker says Power BI “does a fantastic job of combining power analytics with a user-friendly user interface (UI) and remarkable data visualization capabilities,” and adds, “It’s one of the best BI tools on the market and is one of our three Editors’ Choice recipients.”
Industries, where Power BI training comes in handy, include retail, manufacturing, telecommunications and professional services. The service is a game-changer because it allows nontechnical people to easily create graphical reports of data, filter data, share it with others, and much more—no IT department required, meaning even small companies can use it successfully.
Whether you’ve already begun a career in business intelligence, data analysis, ETL (extract, transform, load) and data warehousing or another data-driven area, or you just want to add to your job skills and marketability in the business world, getting a Power BI certification is a smart move. And when you’re preparing for a job interview, make sure you consider these answers to Top Power BI interview questions. While this isn’t a full Power BI tutorial, it will help you get started understanding the basics.
What formats is Power BI available in?
- Power BI desktop—for desktop computers
- Power BI service—an online SaaS (software as a service)
- Mobile Power BI apps—for iOS and Android devices
All of these can be used in conjunction. For example, you might create a report on your desktop, and then publish and share it online so that colleagues on mobile devices can read it.
Describe the building blocks of Power BI.
- Visualizations. A visualization is a chart, graph or similar visual representation of data.
- Datasets. A dataset is the group of data used to create a visualization, such as a column of sales figures. Datasets can be combined and filtered from different sources using built-in connectors.
- Reports. A report is a group of visualizations on one or more pages; for example, charts, graphs, and maps can be combined to create a report.
- Dashboards. A dashboard lets you share a one-page visualization with others, who can then interact with your dashboard.
- Tiles. A tile is a visualization on your dashboard or in your report. As the creator, you can move tiles around.
What are the main components of the Power BI toolkit, and what do they do?
- Power Query: lets you discover, access and consolidate info from different sources
- Power Pivot: a modeling tool
- Power View: a presentation tool for creating charts, tables and more
- Power Map: lets you create geospatial representations of your data
- Power Q&A: lets you use natural language to get answers to questions; for example, “What were the total sales last week?”
What is a content pack, and why would you use one?
A content pack is a ready-made, predefined collection of visualizations and reports using your chosen service (for example, Salesforce). You’d use one when you want to get up and running quickly, instead of creating a report from scratch.
DAX stands for Data Analysis Expressions. It’s a collection of functions, operators, and constants used in formulas to calculate and return values. In other words, it helps you create new info from data you already have.
What are the three fundamental concepts of DAX?
- Syntax. This is how the formula is written—that is, the elements that comprise it. The Syntax includes functions such as SUM (used when you want to add figures). If the syntax isn’t correct, you’ll get an error message.
- Functions. These are formulas that use specific values (also known as arguments) in a certain order to perform a calculation, similar to the functions in Excel. The categories of functions are date/time, time intelligence, information, logical, mathematical, statistical, text, parent/child and other.
- Context. There are two types: row context and filter context. Whenever a formula has a function that applies filters to identify a single row in a table, row context comes into play. When one or more filters are applied in a calculation that determines a result or value, filter context comes into play.
Why and how would you use a custom visual file?
You’d use a custom visual file if the prepackaged files don’t fit the needs of your business. Custom visual files are created by developers, and you can import them and use them in the same way as you would the pre-packaged files.
What are some of the most common sources for data in the Get Data menu?
Excel, Power BI datasets, web, text, SQL server and analysis services.
What are the categories of data types?
- Power BI
- Online Services
Name some commonly used tasks in the Query Editor.
- Connect to data
- Shape and combine data
- Group rows
- Pivot columns
- Create custom columns
- Query formulas
What is grouping, and how would you use it?
Power BI Desktop groups the data in your visuals into chunks. You can, however, define your own groups and bins. For grouping, use Ctrl + click to select multiple elements in the visual. Right-click one of those elements and, from the menu that appears, choose Group. In the Groups window, you can create new groups or modify existing ones.
Describe responsive slicers.
On a report page, you can resize a responsive slicer to different sizes and shapes, and the data contained in it will be rearranged to match. If a visual becomes too small to be useful, an icon representing the visual takes its place, saving space on the report page.
In Power Query, what is query folding?
This is when steps defined in the Query Editor are translated into SQL and executed by the source database, instead of by your own device. It helps with scalability and efficient processing.
Explain the term “M language”.
This is the programming language used in Power Query. It’s a functional, case-sensitive language that’s similar to other programming languages and easy to use.
What are the differences between visual-level filters, page-level filters, and report-level filters?
Visual-level filters filter data within a single visualization. Page-level filters work on an entire page in a report, and different pages can have different filters. Report-level filters filter all the visualizations and pages in the report.
How does the Schedule Refresh feature work?
You can configure an automatic refreshing of data daily or weekly, and at different times. You can schedule only one refresh maximum daily unless you have Power BI Pro. In the Schedule Refresh section, simply use the pulldown menu choices to select frequency, time zone and time of day.
What information is needed to create a map in Power Map?
Power Map can display visualizations that are geographical in nature. Therefore, some kind of location data is needed—for example, city, state, country or latitude and longitude.
Explain Power BI vs. Tableau
Microsoft Power BI and Tableau are both data analytics tools. Power BI has an extensive free version as well as a premium paid version, while Tableau’s free version has limited capabilities. Power BI is considered more intuitive to use than Tableau, as some features in Tableau are hidden behind menus, which makes it harder to learn and use. Power BI has a natural-language query tool, which Tableau doesn’t. Overall, however, Tableau may offer more capabilities for those who are experienced in data analytics. So for the question of Power BI vs. Tableau, Microsoft Power BI is generally considered better for those new to data analytics, especially if they already have experience in Microsoft products such as Excel, Azure and Office 365.
These are just some of the Microsoft Power BI interview questions you might encounter. To learn more answers and get a career-boosting Power BI certification, sign up for Simplilearn’s Power BI training today!
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