25 Must-Know Power BI Interview Questions and Answers (2023)
Power BI Interview Questions: Beginner Level
Let's start with the most basic questions. Simple as they may seem to you, it's always a good idea to be prepared with a confident, comprehensive, and concise answer for each of them.
1. What is Power BI?
Power BI is a cloud-based business intelligence and data visualization software developed by Microsoft to fetch raw data from various sources, transform and analyze it, extract meaningful insights from it, build interactive dashboards and reports reflecting those insights, and share the results with a relevant group of data consumers – your colleagues, managers, or shareholders – to make smart, data-driven business decisions.
2. What are the advantages of Power BI?
There are many advantageous features of Power BI that make it an excellent business intelligence software:
- It’s easy to use, even for non-technical people.
- It has a powerful toolkit for conducting ETL (extraction, transformation, and loading the data).
- It helps share the insights from the data with data consumers.
- It accommodates fast updates of the data in use from the data sources.
- It is equipped with template dashboards and SaaS solution reports.
- It allows real-time dashboard and report updates.
- It allows results displays on various devices (computers, tablets, and mobile phones).
- It ensures quick and safe connection to the data sources in the cloud or locally.
- It enables data querying using natural language processing.
- It provides hybrid configuration and smart deployment.
3. What are some disadvantages of Power BI?
The main disadvantages of Power BI to keep in mind include the following:
- The software is not very intuitive for the beginners.
- Dashboard and report sharing is limited: only users with the same email domain can access the results.
- The majority of data sources don't support real-time connections to Power BI interactive dashboards and reports.
- Power BI for free users can't process datasets larger than 1 GB.
- We can't store an adjusted filter in the saved Power BI visual report filter. In addition, the filter is always displayed on the report, which isn’t always convenient
However, Power Bi is in the process of constant development and improvement, so we can expect the software to overcome some or all of its limitations.
4. What is a common workflow in Power BI?
A standard Power BI workflow includes the following four steps:
- Fetch the data to the Power BI Desktop, clean and manipulate the data, and create a report.
- Publish the report to the Power BI Service and build dashboards.
- Share the dashboards with your colleagues, managers, or shareholders.
- Interact with the final dashboards and reports in Power BI Mobile apps to extract business insights.
5. What are the main business applications of Power BI?
Since Power BI is a business intelligence application, we can apply it to a range of business spheres. Its most crucial applications include the following:
- Extracting meaningful business insights from the available raw data
- Creating compelling live reports and insightful interactive dashboards
- Identifying the current state of different departments or projects
- Tracking progress and KPIs of different departments or projects
- Detecting the strong and weak sides of a project from the standpoint of its performance
- Distributing the roles inside the team
- Granting access to the dashboards and reports to the relevant group of team members
- Displaying various statistics of a certain business on many different applications and websites in a favorable light for a potential customer
6. What kind of specialists typically use Power BI?
The following roles comprise the majority of Power BI users:
- Project managers
- Business analysts
- Data analysts
- Data scientists
- IT specialists
- Data administrators
- Report consumers
7. What is a dashboard in Power BI?
A dashboard in Power BI, also called a canvas, is a single-page selection of the most insightful visualizations taken from the report — those that share the most important highlights of the data-driven story. The end users of Power BI dashboards can access them from various devices (including mobile phones), interact with them to extract valuable business insights, grasp the big picture of the business or project (and the relationships between different parts of the whole).
8. What is Power BI Desktop?
Power BI Desktop is a free and open-source Microsoft application that connects to various data sources, fetches data, cleans and transforms that data, builds a data model, and creates reports and dashboards with meaningful visuals. It also allows users to publish the final reports and dashboards to the cloud through the Power BI Service and share them with other people.
9. What is Power Query?
Power Query is a business intelligence ETL (extract-load-transform) tool developed by Microsoft Excel and available in the Power BI Desktop through the Power Query Editor. With this tool, users can load and combine the data from different data sources like SQL, Oracle, Excel or CSV files, social media, etc., then using the Power Query Editor, users can clean, reshape, transform, and analyze the data. Power Query has an intuitive interface, and it uses the M language under the hood. We also can (even though we don't need to) apply this language to write and modify the code ourselves.
10. What is Power Pivot?
Power Pivot is a built-in component of Microsoft Excel 2010 developed to extend the analytical capability of the application. We can use it to import the data from multiple data sources, store compressed data in a single Excel spreadsheet, build models of tabular data using the DAX (Data Analysis Expression) language, define relationships between different tables, write formulas, calculate new columns, create PivotTables and PivotCharts, apply filters of various levels, and analyze the data.
Power BI Interview Questions: Power BI Structure
In this section, we'll consider some typical questions related to Power BI. They’re mostly basic, but they can sometimes be misleading. Indeed, terms get confused often, like "building blocks," "components," "views," or "elements" of Power BI. Some terms even get used interchangeably, or there isn’t a standard term (e.g., "formats" or "versions"). Fortunately, the question itself usually offers some context on what exactly is in question.
11. What are the main elements of the Power BI package?
There are three main elements of the Power BI package:
- Power BI Desktop — a Microsoft Windows desktop application used to create interactive dashboards and reports for further sharing
- Power BI Service — an online SaaS (Software as a Service) used for publishing reports to the cloud
- Power BI Mobile Apps — available on any device, with native mobile BI apps for Windows, iOS, and Android, so that mobile users of Power BI can view the insights
12. What are the building blocks of Power BI?
Everything we do in Power BI breaks down into the following basic building blocks:
- Visualizations. A visualization, or visual, is a visual representation of the underlying data designed to provide business context and insights that would be difficult to discern from a raw table or text data. In Power BI, we have a variety of visualizations, such as bar charts, pie charts, line graphs, gradient-colored maps, bubble maps, etc.
- Datasets. A dataset is a collection of data, possibly fetched from different data sources, used to create visualizations and reports. Datasets can be Excel sheets, CSV files, Oracle or SQL server tables, and more.
- Reports. A report is a set of interrelated visualizations arranged together on one or more pages to showcase various business insights extracted from the same dataset. Some examples are product sales reports, marketing campaign reports, and sales by company branch reports.
- Dashboards. A dashboard, or canvas, is a selection of the most compelling visuals from the report on one page. It provides insights into the data story we're going to tell to our colleagues, managers, or shareholders. The consumers of a dashboard can view it from various devices and interact with it to get the information they need.
- Tiles. A tile is an individual visual contained in a rectangular block surrounded by other tiles in a report or a dashboard — for example, a single bar chart on a dashboard, or any other visualization.
13. What are the main components of the Power BI toolkit?
Here are the main components of the Power BI toolkit — and what we use them for:
- Power Query: to gather data from various sources and transform it
- Power Pivot: to build data models
- Power View: to create data visualizations
- Power Map: to create 3D geospatial data visualizations
- Power Q&A: to get the answers from the final reports by using natural language
14. What are the different connectivity modes in Power BI?
There are three connectivity modes in Power BI:
- Import mode, aka SQL Server import. This is the default connectivity mode in Power BI since it's used more often than the other two, and it also offers the fastest performance. In this mode, we can import the data into the Power BI Desktop for further querying. However, unless we have Power BI premium, we can't import datasets larger than 1 GB.
- Direct query mode. This mode connects to the data from specific data sources and is particularly efficient at importing large data. Power BI doesn’t store the data itself; it stores its metadata and performs direct queries on the data. The drawback of this connectivity mode is that, in this case, there are limitations on which operations we can perform to manipulate the data.
- Live connection mode. With this connectivity mode, the copy of the data isn't stored in the Power BI model either. Instead, the data source is directly queried every time from Power BI. We can use this mode to access only three data sources: SQL Server Analysis Services, Azure Analysis Services, and Power BI Datasets
15. What types of data sources can Power BI connect to?
The various data sources Power BI can connect to divide into the following groups:
- Files. These can be Excel, CSV, text, or Power BI Desktop files.
- Content packs. These can be from service providers or organizations (i.e., shared by other people in our company).
- Connectors. These connect to databases and datasets such as Azure SQL or SQL Server Analysis Services.
16. What are the different views in the Power BI Desktop?
- Report view. A default view showing the interactive visuals of a report. In this view, we can add and manipulate report pages of various templates, add and adjust visualizations, and publish final reports.
- Data view. In this view, we can implement data shaping and transformation through Query Editor tools, create new calculated columns, and view the data in a table format after it has been fed to the model.
- Relationship view, aka model view. We use it to explore, compare, and manage complex relationships between data models or their subsets.
Power BI Interview Questions: Intermediate level
The last set of questions is more advanced; it can be helpful if you're looking for more senior jobs.
17. Where is the data stored in Power BI?
The data in Power BI is stored in the form of either fact tables (quantitative, usually non-normalized data) or dimension tables (the attributes and dimensions related to the data in a fact table) in one of the two cloud repositories:
- Microsoft Azure Blob Storage: contains the data uploaded by the users
- Microsoft Azure SQL Database: contains all the metadata and the artifacts of the system
For both, encryption and passwords protect the data.
18. What is the difference between Power BI and Tableau?
While both Power BI and Tableau are business intelligence (BI) applications used for business data wrangling, data analysis, and data visualization, there are some significant differences between them:
- Power BI uses DAX (Data Analysis Expression) for calculations, while Tableau uses MDX (Multidimensional Expressions).
- Power BI can work with relatively limited volumes of data, while Tableau easily handles huge volumes.
- Power BI has a relatively easy-to-learn interface that both professionals and beginners can use. The Tableau interface is more challenging, therefore less suitable for beginners.
- Power BI has a smaller range of data sources to connect to, compared to Tableau.
- Power BI is much less expensive than Tableau.
- Power BI is a perfect tool for reporting, while Tableau excels at data visualization.
19. What is the M language in Power BI?
The M language, or M-Code, is a functional, case-sensitive programming language used in the Power Query Editor of Power BI to filter and combine the data through queries.
20. What is DAX in Power BI?
DAX is an acronym for Data Analysis Expressions. It's a functional programming language of Power BI providing a set of functions, operators, and constants that we can use in formulas for computing columns, measures, and tables, as well as overall extraction of new information from the available data. DAX supports various data types: whole and decimal numbers, Boolean, text, date, currency, and N/A.
21. What does self-service business intelligence (SSBI) mean?
SSBI is a set of approaches and tools that enable end users — even those without any background in BI (e.g., sales or marketing teams, product developers, etc.) — to access, manipulate, analyze, and visualize the data in an intuitive way to make strategic, data-driven business decisions.
22. What are content packs in Power BI?
A content pack is a package of Power BI interrelated documents, such as dashboards, reports, and datasets, that are stored as a group. In Power BI, there are two types of such packages: service content packs from services providers like Google Analytics, Marketo, MailChimp, or Twilio that we can access by typing our account data, and organizational content packs created by the users of our company and shared with the entire organization or a selected group of people.
23. How can we define the relationships between two tables in a data model in the Power BI Desktop?
There are two approaches:
- Manual: by using primary and foreign keys
- Automatic: the relationships are identified automatically if the autodetect feature is switched on
To define the relationships between two tables, there shouldn't be any null values or duplicate rows in the data. Also, it's possible to have multiple relationships between tables (represented by dotted lines), but only one of them can be active (represented by a continuous line).
24. What are the different refresh options in Power BI?
There are four refresh options in Power BI:
- Package refresh: synchronizes the Power BI Desktop between the Power BI Service and OneDrive or SharePoint Online without fetching the data from the data source.
- Model refresh, aka data refresh: refreshes the dataset available in the Power BI Service with the data in the original data source.
- Tile refresh: updates the cache for tiles in Power BI on the dashboard every time the data changes (approximately every 15 minutes — or we can also force it).
- Visual container refresh: refreshes the visual container and updates the cached report visuals once the data changes.
25. What types of filters can we use in Power BI reports?
The filters in Power BI can be one of the following types, depending on the scope of their applicability, in descending order:
- Report-level filters: applied to the entire report
- Page-level filters: applied to a particular page of a report
- Visualization-level filters: applied to a single visualization
In this article, we've covered the most typical questions you can expect during a Power Bi interview — and how to answer them. Hopefully, this information will help you prepare for an interview and feel more confident.
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