Power BI is in much more demand, and many organizations prefer to use it. For the aspirants preparing for Power BI, this blog covers the Top 50 Power BI Interview Questions you must prepare in 2021.
The following topics are covered in this blog.
- Power BI Interview Questions – General
- Power BI Interview Question – DAX
- Power BI Interview Question – Power Query
- Power BI Interview Question – Power Pivot
- Power BI Interview Question – Power Map
- Power BI Interview Question – Power View
- Conclusion
Power BI Interview Questions – General
Let’s start the Power BI Interview Questions with a general category where all the basics are discussed.
1) What is BI?
BI refers to Business Intelligence which is the technology-driven flow for analyzing data and delivering actionable information. It helps corporate, business managers, and workers make better business decisions.
2) What is Power BI?
Power BI is a Business Intelligence tool by Microsoft that allows users to load and transform data from various sources into data visualizations, reports, and dashboards. It is an industry-standard tool, and most companies use it for their business solutions.
Learn More: Data Modeling in Power BI
3) Why Power BI?
Power BI is an industry-standard tool by Microsoft for Business Intelligence solutions. Apart from creating visualizations, reports, and dashboards, the primary reasons to choose Power BI are listed below.
- Secure connection to data sources in the cloud or on-premises.
- Real-time data information in dashboards and reports with updates in the dataset.
- Secure environment, fast deployment, and hybrid configuration.
- Easy data exploration with natural language query and machine learning models.
- Access to image recognition, text analytics, and integration with Azure Machine Learning.
4) Name the types of Power BI tools
The Power BI tools available are:
- Power BI Desktop – The desktop tool for computers.
- Power BI Service – Online SaaS tool that can be accessed using any browser.
- Power BI Mobile – Portable tool for mobile users with Android and iOS operating systems.
- Power BI Report Builder – Special tool for creating paginated reports.
Learn More: Paginated Reports
5) What are some data sources that Power BI can connect?
There are various sources that Power BI can connect like:
- Files like Excel (.xlsx, .xlxm), CSV (.csv), Power BI Desktop File (.pbix)
- Content Packs like Data feed, Dataverse, etc.
- Database and datasets like SQL Server, Power BI datasets, and more.
- Web sources like Wikipedia website or any other.
6) Name some important components of the Power BI toolkit
Some important components in the Power BI toolkit are:
- Power Query – It allows to load and transform data from various sources.
- Power Pivot – It is a data modelling tool in Power BI.
- Power View – It is a presentation tool for creating tables, charts, and many more.
- Power Map – It allows the creation of geospatial data representations.
- Power Q/A – It allows the use of natural language to get answers.
7) What is Power BI Gateway?
Power BI Gateway is the tool to access data from the on-premises network. When a user accesses any data from on-premises, the request goes through a Gateway. Power BI Gateway gives a fast and secure connection over the on-premises network and minimizes the chances of interruption in data access due to network failure.
8) Name some types of Power BI Gateway
There are three types of Power BI Gateway.
- On-Premises Data Gateway – It allows several users to connect to multiple on-premises data sources. This data gateway is suited for the scenario where multiple people access multiple data sources.
- On-Premises Data Gateway (Private) – It allows users to connect to sources privately. This data gateway is suited for the scenario where you don’t need to share data with others.
- Virtual Network Gateway – It allows multiple users to connect with multiple data sources secured by virtual networks. It is suited for complex scenarios where multiple people access multiple data sources.
Learn More: Power BI Gateway
9) Can we refresh data when a Power BI report is published in the cloud?
Yes, the data can be refreshed using the gateway. For Sharepoint, the Data Management Gateway is used, and for Power BI, the Personal Data Gateway.
10) Name some different types of refreshing data in Power BI
- Package Refresh – Dataset is updated with the content from the Power BI or Excel files present in OneDrive, Sharepoint, etc., online.
- Data Refresh – Dataset is updated with on-premised data sources using a gateway, and refresh is scheduled.
- Tile Refresh – Dashboard visual tiles are updated regularly in around 15 minutes and can be forced to refresh using the visual menu.
- Visual Container Refresh – Pages in a report that carries visuals are refreshed with updates in data.
11) What do you mean by incremental refresh?
Adding some new data in the source, an increment refresh is done instead of the complete data refresh. In short, Incremental refresh loads the newly added data.
12) In an organization, how can we secure some confidential data in Power BI?
We can use Power BI Row-Level Security to hide confidential data in Power BI. Using Row-Level Security, data is restricted based on the roles created for a profile or group of persons.
Learn More: Row Level Security in Power BI
13) Is it possible to join two unique data sources in the same Power BI dashboard?
Yes, we can join two unique data sources in the same dashboard as long as we have a unique value for each project, task, or resource on both sources.
14) Between two tables, can we create multiple dynamic connections?
No, only one dynamic connection is possible between the two tables.
15) What are some common data shaping techniques?
Some common data shaping techniques are applying for sort order, adding indexes, and removing rows & columns.
16) What is embed code?
Power BI allows publishing the reports on the web. It generates a link address or the embedded code that is shared with others.
17) What are the three Power BI Desktop views tabs?
The three Power BI Desktop views are:
- Report View – The default view shows all the reports containing visualizations, graphs, and charts.
- Data View – This view allows management and modification of the imported data in Power BI.
- Model View – This view allows the management of data models and relationships.
18) Is the Power BI tool free?
Yes, the Power BI tool is available for free, but a user may need to buy a Pro or Premium subscription to access all the additional features.
19) How to hide and unhide a specific report in Power BI?
To hide and unhide specific reports, we need to go to selection Pane in the menu bar and press the hides/unhide toggle button.
20) What is the main prerequisite for connecting to an Azure SQL database?
For connecting to an Azure SQL database, a user needs to configure the firewall setting to allow remote connections.
Power BI Interview Questions – DAX
Now comes the Power BI Interview Questions on DAX, as it is one of the most important parts of Power BI and the most concerned topic for interviews.
21) What is DAX?
DAX refers to Data Analysis Expression, a formula language used for creating calculated measures, columns, fields, and custom tables. It is a collection of constants, operators, and functions to create an expression for calculating values.
Here is a basic sample for DAX expression.
Total Sales = SUM(Sales[SalesAmount])
- Total Sales – It is the measure name that will take the calculated values.
- SUM – It is the DAX function for summing up the values.
- Parenthesis () – This is the parenthesis from which the function takes the argument (value passed to the function).
- Sales – It is the table name from where we want to pick the values.
- SalesAmount – It is the column name of the table where the values are present.
Learn More: DAX in Power BI
22) What are DAX functions?
DAX functions are in-built methods or functions in DAX language that perform some action on the provided data and return some value.
In the above example Total Sales = SUM(Sales[SalesAmount]), SUM is the function used here, to sum up the values present in the SalesAmount.
23) Name some common DAX functions
Here are some common DAX functions that are used frequently.
- Aggregation Functions: SUM, MIN, MAX, AVG, COUNTROWS, DISTINCTCOUNT
- Logical Functions: IF, AND, OR, SWITCH
- Information Functions: ISBLANK, ISFILTERED, ISCROSSFILTERED
- Filter Functions: VALUES, ALL, FILTER, CALCULATE, TOPN
- Date & Time Functions: DATEDIFF, DATEVALUE
- Statistical Functions: GEOMEAN, MEDIAN
- Other Functions: UNION, INTERSECT, EXCEPT, NATURALINNERJOIN, NATURALLEFTEROUTERJOIN,
SUMMARIZECOLUMNS, ISEMPTY, VAR
24) Why TOP N function is not available for page-level filters?
It is not accessible for the page-level filters as their channels are associated with different visuals.
25) What is the use of the INDEX function?
It helps in retrieving the index of the respective row.
26) Why CALCULATE and CALULATETABLE functions are unique?
Only these two functions can filter and modify the table. These can add to existing filters or queries, override filter context of queries and remove existing filter context from queries.
27) What are calculated columns and measures?
Calculated columns are the additional column that we create and calculate using DAX expressions. On the other hand, measures are also calculated using DAX expressions but do not add up in the data tables in any form. Calculated columns are evaluated at each row, and measures are only evaluated at the level of granularity where they are plotted.
28) What are some use cases of DAX?
- DAX can create calculated columns and measures.
- DAX works on the values present in columns.
- DAX can’t calculate rows.
- DAX can’t insert or modify data.
Power BI Interview Questions – Power Query
Now I will cover the important components of the Power BI toolkit one be one. The first component on the list of Power BI Interview Questions is Power Query.
29) What is Power Query?
Power Query is a tool for ETL (Extract, Transform & Load) data with a simple GUI. It allows users to extract data from multiple sources, transform data with their needs and load the final data in the system.
30) Which language is used with Power Query?
Power Query Formula Language, also known as M-code, is the language used in Power Query. It is a simple, easy-to-understand, functional, and case-sensitive language similar to other programming languages.
31) What is Query folding/collapsing in Power BI?
Query folding/collapsing refers to when the steps defined in Power Query are translated into SQL and executed by the source database instead of the client machine.
32) What are the destinations for output in Power Query?
There are two destinations for Power Query output: load to a table in the worksheet and load to an excel data model.
Power BI Interview Questions – Power Pivot
Now comes the Power Pivot component in the list of Power BI Interview Questions.
33) What is Power Pivot?
The Power Pivot is an in-memory data modeling component. It provides highly compressed data storage with fast calculation. It helps you build a data model, relationships, creating formulas, calculated columns, Pivot Tables, and Pivot Charts from multiple resources.
34) What is x-velocity in Power Pivot?
X-Velocity is the in-memory analytics engine behind Power Pivot that loads and handles huge data in Power BI. It stores data in columnar storage that results in faster processing.
35) What is the difference between Data modeling in Power BI and Power Pivot for Excel?
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36) How many active relations can we have between two tables in Power Pivot?
We can only have one active relationship between tables at a time. When a relationship is active (represented with a continuous line), all other relationships will be inactive (represented with a dotted line).
37) What is the limitation of Power Pivot over Power Query?
Power Query is an ETL (Extract, Transform & Load) tool that allows extracting data from various sources and manipulate data based on your need. In contrast, Power Pivot can load data but can not manipulate or transform.
Power BI Interview Questions – Power Map
Let’s get straight to our next important component for Power BI Interview Questions that is Power Map.
38) What is Power Map?
Power Map is a tool for the geographical representation of data in a Bing map. It also supports 3D representation with a collection of millions of geo-coded data points. It gives users the ability to create geographical visualization of data.
39) What are the primary data requirements for using Power Map?
The table loaded in Power Map should have location-based information like latitude, longitude, country, region, state, province, city, zip/pin code, etc.
Power BI Interview Questions – Power View
Now comes the last important component to discuss for Power BI Interview Questions.
40) What is Power View?
Power View is a data visualization technology to create interactive graphs, charts, maps, and many other visuals. It helps in analyzing the data patterns and generating meaningful insights. Power View is available for multiple tools and platforms like Excel, SharePoint, SQL Server, and Power BI.
41) What is Visualization?
Visualization represents data or a set of information in charts, graphs, diagrams, images, and animation. It is an effective way to communicate ideas and data patterns to the whole team. In an organization, visualizations are helpful to management, operation, and other teams who are not much into analyzing the data figures.
42) What is Grouping?
Power BI allows to group data into small chunks in a visualization. For grouping, a user needs to press Ctrl with a click to select the elements in a visual to group them.
43) What are filters?
Filters help in sorting data in Power BI. We can arrange and sort data based on requirements by applying filters. We can use a filter for any visualization, page, report, particular fields, values, and more.
44) Name some types of filters in Power BI reports.
The types of filters in Power BI Reports are:
- Visual-level Filters – It filter all the data present in a single visualization.
- Page-level Filters – It filter all the data on a single page of the report.
- Report-level Filters – It filter all the data in the complete report.
45) What are the processes of dynamic filtering?
The steps of dynamic filtering are:
- Make all the data of a report ready to be published
- Publish report into the group workspace
- Create a filter link
- Create a DAX calculated column
- Public overview report
46) What is the difference between Filter and Slicer?
In a normal filter, the user cannot interact with the dashboard, whereas a slicer allows users to interact with Reports and Dashboards.
47) What are custom visuals?
There is a limited number of visuals in Power BI and one may need to add some custom visuals in Power BI. The visuals that are imported in Power BI from external sources are called custom visuals.
48) What is z-order in Power BI?
It is a design strategy that is used for arranging visuals over shapes. In other words, it is an implementation method that can be applied whenever reports have multiple elements.
49) How to compare target and actual value in Power BI?
Using Gauge charts, we can compare two different measures, including the target and actual value.
50) What is Time-Series Analysis?
Time Series helps you analyze the data patterns like trends, cyclicity, and seasonality with time-based graphs and visualizations. It is an effective way of representing data that changes over time to see the patterns clearly. It is widely used for analyzing events, forecasting, and prediction.
Learn More: Data Analysis in Power BI
Conclusion
Power BI is a perfect Business Intelligence tool that most organizations prefer to use. With the increase in demand for Power BI, most companies look for skilled aspirants as their employees. An interview is a must to secure a job, so we have covered some most preferred topics for the Power BI Interview Questions.
If you are planning to become a Power BI expert and get certified, check our Microsoft Power BI Data Analyst Certification course below.
References
- Introduction to Microsoft Power BI Platform | Everything You Must Know
- Exam PL-300: Microsoft Power BI Data Analyst | A Replacement Of DA-100
- Microsoft Certified Data Analyst Associate [PL-300] Step By Step Activity Guides (Hands-On Labs)
- Case Study: Display Live Data Streaming Using Power BI Service
- Introduction to Data Modeling in Power BI
- What is Power Query | Microsoft Azure Power BI Tool
- Top 15 Differences Between SSRS vs Power BI
- How to Become a Power BI Developer?
- Table and Matrix Visualization in Power BI
Next Steps to begin with PL-300 Certification:
In our PL-300 Certification Training Program, we’ll cover 10+ Hands-On Labs. If you wish to start your journey towards becoming a Microsoft Certified: Power BI Data Analyst Associate, try our FREE CLASS.
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