Top 50 Power BI Interview Questions & Answers (for Freshers)
7 minute read
If you’re preparing for your first data analyst role, these 50 interview questions and answers will help you get ready.
1. What is Power BI? Power BI is a business analytics tool by Microsoft that lets you visualize data, share insights, and make data-driven decisions using interactive dashboards and reports.
2. Main components of Power BI?
Power BI Desktop – Create reports
Power BI Service – Share reports online
Power BI Mobile – View on phones/tablets
Power BI Gateway – Refresh data from on-premises
Power BI Report Server – Host reports on-premises
3. Power BI Desktop vs Power BI Service?
Desktop is for building reports (offline).
Service is for publishing, sharing, scheduling, and collaboration (online).
4. What data sources can Power BI connect to?
Excel, SQL Server, SharePoint, Web, APIs, Azure, Oracle, Google Analytics, and many more.
5. What is DAX?
DAX (Data Analysis Expressions) is a formula language used in Power BI to create custom calculations and expressions like measures and calculated columns.
6. What is the importance of relationships in Power BI?
Relationships link tables, allowing you to create visuals using fields from multiple tables, like in a relational database.
7. Star vs Snowflake schema?
Star: Facts connect to dimension tables directly.
Snowflake: Dimension tables are normalized (split into sub-tables).
8. Calculated Column vs Measure?
Calculated Column: Row-level, stored in the model.
Measure: Calculated at query time, based on filters.
9. SUM vs SUMX in DAX?
SUM: Adds up a column directly.
SUMX: Iterates through rows, applies an expression, and sums the results.
10. What is an inactive relationship?
A relationship that is not used by default in visuals. You can activate it using DAX (USERELATIONSHIP())
11. What is CALCULATE() in DAX?
Changes the context in which a calculation is performed. It’s key for complex measures.
12. How does FILTER() work in DAX?
Returns a table that meets a condition. Used to modify context inside CALCULATE().
13. ALL vs ALLEXCEPT vs ALLSELECTED?
ALL: Removes all filters.
ALLEXCEPT: Keeps specified filters.
ALLSELECTED: Keeps filters applied by visuals.
14. EARLIER vs EARLIEST?
Used in row context to refer to outer row values in nested calculations.
15. What is context transition?
When row context turns into filter context – happens in measures using CALCULATE().
16. How to create custom visuals?
Use Power BI marketplace.
Or create with TypeScript & D3.js (for advanced).
17. Slicer vs Filter?
Slicer: Visual-level, user-interactive.
Filter: Can be applied at visual, page, or report level.
18. What is Drill-through in Power BI?
A feature to jump to a detailed report page with filters based on a selected value.
19. What are Bookmarks used for?
Capture report view states – used for storytelling, navigation, and toggling visuals.
20. How to optimize performance in Power BI?
Use Import mode
Reduce columns
Use star schema
Avoid complex measures
Use summary tables
21. What is Power Query?
A data connection and transformation tool using the M language for cleaning and shaping data before loading it.
22. Merge vs Append in Power Query?
Merge: Join tables (like SQL JOIN).
Append: Stack tables (like UNION).
23. What is Query Folding?
When transformations in Power Query are pushed to the data source, improving performance.
24. Import vs DirectQuery?
Import: Loads data into memory (faster).
DirectQuery: Queries source live (real-time, slower).
25. How to handle nulls in Power Query?
Use “Replace Values”, “Remove Rows”, or custom logic to fill/replace nulls.
26. What is Row-Level Security (RLS)?
A way to restrict data access for users based on roles – implemented via DAX filters.
27. Dashboard vs Report?
Dashboard: Single page, visual summary.
Report: Multi-page, interactive, built in Desktop.
28. How to schedule data refresh?
In Power BI Service: Go to Dataset → Settings → Configure refresh schedule.
29. Can Power BI be embedded in apps?
Yes, using Power BI Embedded (Azure service) with REST APIs or iframe.
30. Power BI Free vs Pro vs Premium?
Free: For personal use.
Pro: Share, collaborate, publish.
Premium: Enterprise-level, higher capacity, paginated reports, AI features.
31. How do you implement row-level security (RLS) in Power BI?
Go to Modeling → Manage Roles → Create Role, define DAX filters (e.g., [Region] = "East"), and publish to Power BI Service to assign users.
32. What are KPIs in Power BI?
KPIs (Key Performance Indicators) are visual cues that show progress toward a measurable goal – created using indicator, target, and status fields.
33. Difference between filter context and row context?
Filter context: Applied by visuals, slicers, filters.
Row context: Iteration over rows in calculated columns or functions like SUMX.
34. Can we use multiple data sources in a single Power BI report?
Yes. Power BI can connect and combine multiple sources (Excel + SQL + Web) using Power Query and relationships.
35. What is Composite Model in Power BI?
A model that combines Import and DirectQuery data sources, offering more flexibility in data modeling.
36. What is the use of the LOOKUPVALUE function?
LOOKUPVALUE retrieves a single value from another table based on a search condition, similar to VLOOKUP in Excel.
37. What are Quick Measures in Power BI?
Pre-built DAX templates for common calculations like YTD, running totals, etc., created using drag-and-drop interface.
38. How to create a hierarchy in Power BI?
Drag and drop related fields (e.g., Year → Month → Day) in the Fields pane to form a drill-down hierarchy.
39. What is the role of the Power BI Gateway?
It bridges cloud-based Power BI Service and on-premises data sources for scheduled refreshes and live connections.
40. What is incremental refresh in Power BI?
Loads only new or updated data instead of full dataset every time. Improves performance for large datasets.
41. How to handle many-to-many relationships in Power BI?
Use a bridge table or composite models, and enable “Both” direction in relationships cautiously.
42. What are role-playing dimensions?
A single dimension (e.g., Date) used in multiple contexts (Order Date, Ship Date) – handled via multiple relationships.
43. How to create dynamic titles in Power BI visuals?
Use a DAX measure like SelectedValue() and bind it to the title via “fx” (expression) option in the visual’s format pane.
44. What are parameters in Power BI?
Used in Power Query to define values that can dynamically change (e.g., file paths, filters, limits).
45. How to troubleshoot a slow Power BI report?
Check DAX efficiency
Use fewer visuals
Disable auto-date
Remove unnecessary columns
Enable performance analyzer
46. What are paginated reports in Power BI?
Pixel-perfect, printable reports created using Power BI Report Builder, supported only in Premium workspace.
47. How does drill-down vs drill-through work?
Drill-down: Explore hierarchical data in same visual.
Drill-through: Jump to another report page with filters passed.
48. Can you connect Power BI to live web APIs?
Yes, using Web connector or Power Query (M language) to call REST APIs and retrieve JSON/XML data.
49. What are the limitations of DirectQuery mode?
Slower performance
Limited DAX functions
1M row visual limit
No native support for time intelligence
50. How do bookmarks enhance storytelling in Power BI?
Bookmarks capture report state (filters, visuals) and allow interactive navigation or guided walkthroughs when combined with buttons.
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