Power BI FAQ: 100 Questions for Interview Preparation
Power BI FAQ: 100 Questions for Interview Preparation
Welcome to this comprehensive resource for Power BI interview preparation! This guide compiles 100 frequently asked questions and answers that will help you boost your confidence before your next interview. Feel free to share this on social media using the buttons below!
🔹 Power BI Basics (Q1-Q10)
| No. |
Question |
Answer |
| 1 | What is Power BI? | A business intelligence tool by Microsoft for data visualization, reporting, and analytics. |
| 2 | What are the main components of Power BI? | Power BI Desktop (report creation), Power BI Service (cloud sharing), Power BI Mobile (app access). |
| 3 | Is Power BI free? | Power BI Desktop is free, but Pro/Premium requires a paid license for collaboration. |
| 4 | What is Power Query? | A data transformation tool in Power BI for cleaning and shaping data. |
| 5 | What is DAX? | Data Analysis Expressions (DAX) is a formula language for calculations & modeling. |
| 6 | What is Power Pivot? | A data modeling tool in Excel & Power BI for creating relationships. |
| 7 | What is Power View? | An interactive visualization tool in Excel & Power BI. |
| 8 | What is Power Map? | A 3D geospatial visualization tool (now part of Power BI). |
| 9 | What is Power BI Report Server? | An on-premises solution for hosting Power BI reports. |
| 10 | What are Power BI Templates (.pbit files)? | Pre-designed report templates for quick deployment. |
🔹 Data Loading & Transformation (Q11-Q20)
| No. |
Question |
Answer |
| 11 | What are common data sources in Power BI? | Excel, SQL, CSV, Web, SharePoint, Salesforce, Azure. |
| 12 | How to remove duplicates in Power Query? | Right-click column > Remove Duplicates. |
| 13 | What is "Unpivot" in Power BI? | Converts columns into rows (normalizes data). |
| 14 | How to merge queries? | Home > Merge Queries (supports Inner, Left, Right, Full Outer joins). |
| 15 | What is "Append Queries"? | Combines rows from multiple tables with the same structure. |
| 16 | How to replace null values? | Transform > Replace Values > (Null → 0/Blank). |
| 17 | What is "Group By" in Power Query? | Aggregates data (Sum, Avg, Count) by a category. |
| 18 | How to split columns? | Right-click column > Split Column (by delimiter/fixed length). |
| 19 | What is "Parameters" in Power Query? | Dynamic variables for reusable queries. |
| 20 | How to handle errors in Power Query? | Right-click error > Replace/Remove Errors. |
🔹 Data Modeling & Relationships (Q21-Q30)
| No. |
Question |
Answer |
| 21 | What is a Star Schema? | A fact table linked to dimension tables. |
| 22 | What are relationship types? | One-to-One, One-to-Many, Many-to-One, Many-to-Many. |
| 23 | What is Cross-Filter Direction? | Single (one-way) or Both (bi-directional). |
| 24 | When to use DirectQuery vs Import Mode? | Import = faster, DirectQuery = live data. |
| 25 | What is USERELATIONSHIP() in DAX? | Forces a specific relationship in calculations. |
| 26 | What is "Inactive Relationship"? | A relationship not used by default (activated via DAX). |
| 27 | What is "Calculated Table"? | A table created using DAX formulas. |
| 28 | How to optimize data models? | Use star schema, avoid circular dependencies, limit columns. |
| 29 | What is "Bidirectional Filtering"? | Allows filters to propagate both ways in relationships. |
| 30 | What is "Hiding Fields" in Power BI? | Makes columns invisible in reports but keeps them in the model. |
🔹 DAX & Calculations (Q31-Q40)
| No. |
Question |
Answer |
| 31 | What is the difference between CALCULATE() and SUM()? | SUM() adds values; CALCULATE() modifies filter context. |
| 32 | What is TOTALYTD()? | Calculates Year-to-Date totals. |
| 33 | What is the difference between MEASURE and CALCULATED COLUMN? | Measure = dynamic, Column = static. |
| 34 | What is FILTER() in DAX? | Filters a table (e.g., CALCULATE(SUM(Sales), FILTER(...))). |
| 35 | What is EARLIER() in DAX? | References an earlier row context (rarely used now). |
| 36 | What is SAMEPERIODLASTYEAR()? | Compares data with the same period last year. |
| 37 | What is RANKX()? | Ranks data based on a measure (e.g., RANKX(Products, Sales)). |
| 38 | What is SELECTEDVALUE()? | Returns a single value from a slicer. |
| 39 | What is ALL() in DAX? | Removes filters from a table/column. |
| 40 | What is DIVIDE()? | Safely divides numbers (handles divide-by-zero errors). |
🔹 Visualization & Reports (Q41-Q50)
| No. |
Question |
Answer |
| 41 | What is the best chart for trends? | Line Chart (time on X-axis). |
| 42 | When to use a Matrix Visual? | For hierarchical data (e.g., Year > Quarter > Month). |
| 43 | What is Drill-Through? | Click a data point to navigate to a detailed page. |
| 44 | How to use Tooltips? | Add additional visuals in the Tooltip pane. |
| 45 | What are Bookmarks? | Save filter & visual states for interactivity. |
| 46 | What is "Edit Interactions"? | Controls how visuals affect each other. |
| 47 | How to export Power BI data? | Right-click visual > Export Data (CSV/Excel). |
| 48 | What is "Q&A Visual"? | Allows natural language queries (e.g., "Show sales by region"). |
| 49 | How to schedule data refresh? | Power BI Service > Dataset > Schedule Refresh. |
| 50 | What is Row-Level Security (RLS)? | Restricts data access based on user roles. |
🔹 Advanced Power BI Concepts (Q51-Q100)
📌 Performance Optimization & Troubleshooting
| No. |
Question |
Answer |
| 51 | How to optimize slow Power BI reports? | Use aggregations, limit visuals, optimize DAX, switch to DirectQuery if needed. |
| 52 | What is Performance Analyzer? | A tool to identify slow visuals/queries in Power BI Desktop. |
| 53 | How to reduce Power BI file size? | Remove unused columns, use integer/date instead of text, disable auto-date. |
| 54 | What is VertiPaq engine? | Power BI’s in-memory compression engine for fast queries. |
| 55 | Why is my measure returning blank values? | Check filters, relationships, or use IF(ISBLANK(), "N/A", value). |
📌 Power BI Service & Cloud Features
| No. |
Question |
Answer |
| 56 | What is Power BI Gateway? | Connects on-prem data to Power BI Cloud (Personal/Enterprise modes). |
| 57 | How to share dashboards in Power BI Service? | Publish to workspace > Share button (requires Pro license). |
| 58 | What is Power BI Premium? | Enterprise plan for larger datasets, paginated reports, and AI. |
| 59 | What is Power BI Embedded? | Embed reports into custom apps/websites (for developers). |
| 60 | How to set up data alerts? | In Power BI Service, click the bell icon on a visual. |
📌 Advanced DAX & Time Intelligence
| No. |
Question |
Answer |
| 61 | What is time intelligence in DAX? | Functions like TOTALYTD(), SAMEPERIODLASTYEAR() for time-based analysis. |
| 62 | How to calculate moving averages? | Use AVERAGEX(DATESINPERIOD(), [Measure]). |
| 63 | What is semi-additive measure? | A measure that doesn’t sum across time (e.g., inventory levels). |
| 64 | How to use variables (VAR) in DAX? | Improves performance & readability. |
| 65 | What is BLANK() vs ISBLANK()? | BLANK() returns a blank, ISBLANK() checks if a value is blank. |
📌 Dataflows & AI Integration
| No. |
Question |
Answer |
| 66 | What is Power BI Dataflow? | Reusable ETL pipelines in Power BI Service. |
| 67 | How to use AI visuals? | Enable Q&A, Key Influencers, Decomposition Tree. |
| 68 | What is AutoML in Power BI? | Automated machine learning for predictive analytics. |
| 69 | How to use Python/R in Power BI? | Enable in Options > Scripting, then use in Power Query/Visuals. |
| 70 | What is Cognitive Services in Power BI? | Pre-built AI models (sentiment analysis, image recognition). |
📌 Real-World Scenarios
| No. |
Question |
Answer |
| 71 | How to build a KPI dashboard? | Use Cards, Gauges, Trendlines with DAX measures. |
| 72 | How to handle slow DirectQuery? | Optimize SQL queries, add indexes, use aggregations. |
| 73 | How to create a dynamic title? | Use a measure: Title = "Sales: " & SELECTEDVALUE(Region[Name], "All Regions"). |
| 74 | How to implement hierarchical drilldown? | Use Matrix/Chart hierarchies (e.g., Year > Quarter > Month). |
| 75 | How to compare two periods? | Use DATEADD() or SAMEPERIODLASTYEAR(). |
📌 Deployment & Security
| No. |
Question |
Answer |
| 76 | What is Deployment Pipeline? | A Power BI Premium feature for dev/test/prod environments. |
| 77 | How to export to PDF? | File > Export > PDF (or use Power BI Service). |
| 78 | What is Power BI Apps? | Pre-packaged reports for end-users (no editing). |
| 79 | How to audit Power BI usage? | Use Microsoft 365 Admin Center or Power BI Activity Log. |
| 80 | What is BYOL (Bring Your Own License)? | Allows using Pro licenses in Premium workspaces. |
📌 Advanced Visualization Techniques
| No. |
Question |
Answer |
| 81 | How to create custom tooltips? | Add a tooltip page with detailed visuals. |
| 82 | What is small multiples? | Repeats a visual for each category (e.g., line charts per region). |
| 83 | How to use conditional formatting? | Right-click visual > Conditional formatting (color/data bars). |
| 84 | What is drillthrough vs cross-filtering? | Drillthrough = navigate to another page, cross-filter = highlight related data. |
| 85 | How to add bookmark navigation? | Create buttons linked to bookmarks. |
📌 Power BI Integrations
| No. |
Question |
Answer |
| 86 | How to connect to Azure Synapse? | Use DirectQuery/Import with Azure SQL connector. |
| 87 | What is Power BI Paginated Reports? | Pixel-perfect reports (SSRS) for printing/PDFs. |
| 88 | How to use Power Automate with Power BI? | Trigger flows when data refreshes/alerts fire. |
| 89 | How to embed Power BI in SharePoint? | Use "Embed" web part or Publish to Web (public). |
| 90 | What is Power BI Goals? | Track KPIs with status, due dates, and owners. |
📌 Tricky Interview Questions
| No. |
Question |
Answer |
| 91 | How to handle circular dependencies? | Use DISTINCT() or redesign the model. |
| 92 | What is shadow filtering? | Hidden filters from bi-directional relationships. |
| 93 | How to debug DAX performance issues? | Use DAX Studio or Performance Analyzer. |
| 94 | What is calculation groups? | A tabular model feature to reuse logic (not native in Power BI). |
| 95 | How to simulate GROUP BY in DAX? | Use SUMMARIZE() or GROUPBY(). |
📌 Future of Power BI
| No. |
Question |
Answer |
| 96 | What is Power BI Copilot? | AI-powered natural language report building. |
| 97 | How does Fabric integrate with Power BI? | Microsoft’s unified data analytics platform. |
| 98 | What is Direct Lake mode? | Queries Parquet files directly (no import/DQ). |
| 99 | What are Power BI Goals? | Track business metrics with real-time updates. |
| 100 | How to stay updated on Power BI? | Follow the Microsoft Power BI Blog, attend Power BI Summit. |
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