Here, we will discuss PowerBI Interview Questions, which interviewers mainly ask for a Power BI Analyst or Data Analytics Position in company interviews.
Table of Contents
1. What is Power BI?
Power BI is Microsoft’s business analytics tool for visualizing data, generating insights, and sharing reports. It integrates with multiple data sources, transforms raw data via Power Query, and creates interactive dashboards.
With DAX for calculations, cloud collaboration via Power BI Service, and mobile access, it enables data-driven decisions for technical and non-technical users.
2. Power BI Interview Topics
- Core Concepts: Data modeling, relationships (star schema), ETL with Power Query.
- DAX: Formulas, time intelligence, calculated columns vs. measures.
- Visualization: Best practices, custom visuals, drill-through, bookmarks.
- Technical: Row-level security, performance optimization, data gateways.
- Deployment: Publishing reports, Power BI Service vs. Desktop, sharing dashboards.
- Advanced: DirectQuery vs. Import, incremental refresh, integration (Azure, Excel).
- Scenario-Based: Troubleshooting data issues, real-time analytics, translating business requirements into solutions
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PowerBI Interview Questions
1. What are parameters?
Parameters in Power BI are dynamic values that can filter data, modify queries, or customize reports.
They allow users to input values that can change the report’s behavior without altering the underlying data model.
2. What is a sparkline?
A sparkline is a small, simple chart embedded within a cell of a table or matrix that provides a visual representation of data trends over time. Sparklines are often used to show trends in a compact format without axes or labels.
3. How would you implement joins with fuzzy matching?
Fuzzy matching in Power BI can be implemented using the Merge Queries feature in Power Query.
By enabling the “Fuzzy Matching” option, users can join tables based on similar text values, allowing for variations in spelling or formatting.
4. What is the maximum number of rows that can be imported in DQ and import storage modes?
In Power BI, the maximum number of rows that can be imported in Import mode is approximately 2 billion rows per table.
While DirectQuery (DQ) does not impose a strict row limit, performance can degrade with larger datasets.
5. What are functions in Power Query?
Functions in Power Query are reusable formulas that perform calculations or transformations on data.
They can accept parameters and return values, allowing for dynamic data manipulation and cleaner query design.
6. What are the 3 modes to pull data into Power BI?
The three modes to pull data into Power BI are Import Mode (data is imported into Power BI), DirectQuery Mode (data remains in the source and queries are sent in real-time), and Live Connection (a direct connection to a live data source, often used with Analysis Services).
7. When to use live connection vs import mode?
Use Live Connection when real-time data access is crucial, such as for operational dashboards.
Import Mode is preferable for static data that doesn’t change often, allowing for faster performance and more advanced modeling capabilities.
8. How to refresh the connection in import mode?
To refresh data in Import Mode, you can set up a scheduled refresh in the Power BI service or manually refresh it in Power BI Desktop by clicking the “Refresh” button, which updates the dataset with the latest data from the source.
9. How to refresh data across time zones?
To refresh data across time zones, you can use UTC timestamps in your data model and adjust for local time zones in your reports.
This ensures that the data reflects the correct local time regardless of where the refresh occurs.
10. What are Data Gateways?
Data Gateways are software components that facilitate secure data transfer between on-premises data sources and Power BI services in the cloud. They enable scheduled refreshes and live queries without exposing sensitive data directly to the internet.
11. What is Conditional Formatting, and how do you apply it to the visuals?
Conditional Formatting in Power BI allows users to change the appearance of visuals based on the values of the data.
It can be applied by selecting a visual, navigating to the formatting pane, and setting rules for color scales, data bars, or icons based on specific conditions.
12. Have you worked with Gantt Charts?
Yes, Gantt Charts are used in Power BI to visualize project timelines and task durations.
They can be created using custom visuals or by formatting a bar chart to represent start and end dates, providing insights into project schedules.
13. What is RLS? How do you filter rows based on user information like email or user ID?
Row-Level Security (RLS) restricts data access for users based on their roles.
You can implement RLS by defining security roles in Power BI Desktop and using DAX expressions to filter data based on user attributes, such as email or user ID.
14. What are the different data sources you’ve pulled into Power BI?
Common data sources include SQL Server, Excel, SharePoint, Azure services, and web APIs.
Each source provides various data types and structures, allowing for diverse analytical capabilities within Power BI.
15. Have you used APIs to pull data? What are basic and token authentication methods for APIs?
Yes, APIs can be used to pull data into Power BI. Basic authentication involves sending a username and password with requests.
While token authentication requires an access token that is generated after a successful login, it enhances security.
