The rising need for organizations to make decisions based on data has increased the demand for competent professionals who can use business intelligence tools such as Power BI effectively. Power BI is a strong analytics service that helps users to visualize data and share insights with their organizations. In this chapter, we are going to learn some basic questions about Power BI asked in the interview for freshers. All these questions address the most significant concepts, functionalities, and benefits of Power BI, creating an excellent ground for understanding this versatile tool.
Q. What is Power BI?
Power BI is a business analytics service that provides interactive visualizations and business intelligence capabilities. It allows users to create reports and dashboards from various data sources, facilitating data-driven decision-making within organizations. To gain detailed insights on Microsoft Power BI from scratch go through our blog – What is Power BI, covering everything for basics to advanced.
Q. Why should we use Power BI?
Power BI offers several advantages, including user-friendly interfaces, robust data visualization capabilities, integration with other Microsoft products, and the ability to handle large datasets efficiently. This makes it an ideal choice for businesses looking to enhance their data analysis processes.
Q. Difference between Power BI and Tableau
Both tools are used for data visualization, but Power BI is more integrated with Microsoft products, making it easier for users in Microsoft environments. Tableau offers more advanced visualization options and is often preferred for complex analytics tasks.
For further details on Microsoft-related courses including Power BI, you can explore our Microsoft Training page.
Q. Difference between Power Query and Power Pivot
Power Query is used for data extraction and transformation, allowing users to clean and shape their data before analysis. Power Pivot, on the other hand, is focused on data modeling and allows users to create relationships between different datasets.
Q. What is Power BI Desktop?
Power BI Desktop is a free application that allows users to create reports and dashboards by connecting to various data sources. It provides tools for data modeling, visualization, and report design.
Q. What is Power Pivot?
Power Pivot is an Excel add-in that allows users to perform powerful data analysis and create sophisticated data models. It enables users to work with large datasets efficiently using in-memory technology.
Q. What is Power Query?
Power Query is a data connection technology that enables users to discover, connect, combine, and refine data across a wide variety of sources. It simplifies the process of preparing data for analysis.
Q. Describe the components of Microsoft’s self-service BI solution?
Microsoft’s self-service BI solution includes components like Power BI Desktop for report creation, Power Query for data preparation, Power Pivot for modeling, and Power BI Service for sharing reports online.
Q. What is self-service BI?
Self-service BI empowers end-users to access and analyze data independently without relying on IT departments. It allows users to create reports and dashboards tailored to their specific needs.
Q. What is DAX?
DAX (Data Analysis Expressions) is a formula language used in Power BI for creating custom calculations in reports. It includes functions for filtering, aggregating, and manipulating data.
Q. What are Filters in Power BI?
Filters in Power BI allow users to limit the data displayed in reports or visuals based on specific criteria. They can be applied at various levels: visual-level, page-level, or report-level.
Q. What are Custom Visuals in Power BI?
Custom visuals are user-created visualizations that can be imported into Power BI reports. They extend the standard set of visuals available in Power BI by providing unique ways to display data.
Q. What is GetData in Power BI?
GetData is a feature in Power BI that allows users to connect to various data sources such as databases, Excel files, web services, and more. It serves as the starting point for importing data into the application.
Q. Mention some advantages of Power BI.
Advantages include ease of use, integration with other Microsoft tools (like Excel), real-time dashboard updates, extensive visualization options, and strong community support.
Q. List out some drawbacks/limitations of using Power BI.
Limitations include restrictions on dataset size (for free versions), dependency on internet connectivity for cloud features, potential performance issues with very large datasets, and limited customization options compared to some competitors.
Q. What are some differences in data modeling between Power BI Desktop and Power Pivot for Excel?
While both tools allow for creating relationships between tables and building models, Power BI Desktop supports more advanced features like direct query connections and real-time collaboration through the cloud.
Q. Name the different connectivity modes available in Power BI.
The main connectivity modes are:
- Import Mode: Data is imported into the model.
- DirectQuery Mode: Queries are sent directly to the source database.
- Live Connection: A direct connection to an Analysis Services model or Azure Analysis Services.
Q. What are the various types of refresh options provided in Power BI?
Refresh options include:
- Manual Refresh: Users refresh datasets manually.
- Scheduled Refresh: Automatic refresh at specified intervals.
- DirectQuery: Real-time querying of live databases without needing refreshes.
Q. What are the different types of data sources you can connect to in Power BI?
Users can connect to a wide range of sources including SQL Server databases, Excel files, cloud services (like Azure), web APIs, SharePoint lists, and many more.
Q. What is a dashboard in Power BI?
A dashboard is a single-page interface that displays key metrics through visualizations from multiple reports. It provides a high-level overview of performance indicators at a glance.
Q. Explain how relationships are defined in Power BI Desktop?
Relationships can be defined manually by specifying primary and foreign keys or automatically through the model’s auto-detect feature which identifies relationships based on matching column names.
Q. Can you have more than one functional relationship between two tables in a Power Pivot data model?
No, only one active relationship can exist between two tables at any time; however, multiple inactive relationships can be defined which can be activated using DAX functions like USERELATIONSHIP. Learn more on how you can create relationships between multiple Power BI tables.
Q. Can you have a table in the model which does not have any relationship with other tables?
Yes, it’s possible to have standalone tables without relationships; they can still be used within measures or calculations but won’t interact with other tables’ filters or context.
Q. What is the CALCULATE function in DAX?
CALCULATE modifies the filter context applied to a calculation by evaluating an expression under new filter conditions specified by additional arguments.
Q. How do you connect to data in Power BI?
Users connect to data by selecting “Get Data” from the Home tab in Power BI Desktop. They then choose their desired source type (e.g., Excel file or SQL database) and follow prompts to establish the connection.
Q. How do you publish a report in Power BI?
Reports created in Power BI Desktop can be published directly to the Power BI Service by clicking on the “Publish” button found on the Home ribbon after signing into your account.
Q. What is a calculated column in Power BI?
A calculated column adds new column values based on DAX formulas applied row by row within a table during data load or refresh processes.
Q. What is a measure in Power BI?
A measure performs calculations on aggregated values dynamically based on filters applied within reports; they are recalculated based on user interactions with visuals.
Q. What is a Fact Table and Dimension Table in Power BI?
A Fact Table contains quantitative data (metrics) for analysis while Dimension Tables contain descriptive attributes related to facts (like time periods or product categories).
Q. What are the rules regarding Dimension Tables?
Dimension Tables should contain unique values as primary keys; they should also be denormalized where possible to optimize performance during queries.
Q. How do you connect a Fact Table and a Dimension Table in Power BI?
Connections are made by establishing relationships based on common fields (keys) such as foreign keys from Fact Tables pointing back to primary keys in Dimension Tables.
Q. What are the different languages used in Power BI?
The primary languages include DAX for calculations within models and M language used within queries for transforming raw data during import processes via Power Query.
Q. What is the easiest method to navigate in Power BI?
The easiest navigation method involves using bookmarks for quick access between views or utilizing drill-through features within reports for detailed insights into specific metrics.
Q. What is Power BI, Business Intelligence and its key features?
Power BI is a data visualization tool developed by Microsoft. It enables users to establish connections with diverse data sources, transform and manipulate data, generate interactive reports and dashboards and share insights with others. Power BI is extensively used in organizations to analyze data and make informed decisions based on data-driven insights.
BI stands for Business Intelligence which refers to collecting, analyzing and delivering business data to support decision-making in organizations This system uses a variety of tools, applications and practices to transform raw data and organise them into valuable insights. By doing so, companies can make informed decisions, spot trends and improve their overall performance.
Power BI is a useful tool with many features. Some notable features include:
- It enables users to visualize data and share that visualization with others.
- Users are able to browse and examine data from all sources (in a unified view).
- Users may scale across enterprises while benefiting from integrated governance and security.
- Users can see an output once it has been generated on any device that supports the Power BI application.
- Users can run queries on reports using basic English terms.
- Q.
Implement Row-Level Security (RLS) in Power BI. - Define roles in Power BI Desktop (e.g., [Region] = USERPRINCIPALNAME() mapping).
- Publish report to Power BI Service and assign roles to specific users.
Q. How to create a dynamic title for your report page that changes based on the selected year.
Use a Card visual with a measure:
DynamicTitle = “Sales Report for ” & SELECTEDVALUE(Date[Year])
Q. You want to combine multiple date tables into one master date table. How do you do it?
- Use Power Query
- Append Queries
- Combine all date tables
- Remove duplicates.
MasterDate = Table.Distinct(Table.Combine({Date1, Date2, Date3}))
Q. How to show a trend of cumulative sales over the year.
Create a Running Total measure in DAX:
Cumulative Sales = CALCULATE(SUM(Sales[Amount]), FILTER(ALL(Date), Date[Date] <= MAX(Date[Date])))
Q. How to Remove Null and Duplicate Values in Power BI
1. Removing Null Values:
- Go to Power Query Editor.
- Select the column(s) where you want to remove nulls.
- From the Home tab → Remove Rows → Remove Blank Rows.
Example: If a CustomerID column has null values, they will be removed.
2. Removing Duplicate Values:
- In Power Query Editor, select the column(s) where duplicates may exist.
- From the Home tab → Remove Rows → Remove Duplicates.
Example: If the Sales table has duplicate OrderID, selecting OrderID and removing duplicates will keep only unique orders.
Q. What is KPI in Power BI?
A KPI (Key Performance Indicator) in Power BI is a visual used to track progress toward a specific goal or business target. It helps measure performance by comparing actual values against a target value.
- KPI visuals show status (current value), target (goal) and trend (progress over time).
- Useful for monitoring metrics like sales vs. target, revenue growth, customer satisfaction, etc.
- Created using measures in DAX (for actual and target values).
Example: If you want to track Sales Performance:
- Actual Sales = SUM(Sales[Amount])
- Target Sales = 1,00,000
- KPI visual shows whether actual sales are below, meeting or above the target.
Q. What are Add-ins in Power BI?
Add-ins in Power BI are extra tools or extensions that you can integrate with Power BI to extend its functionality. They allow users to bring in advanced visuals, connect with other applications or use specialized features that aren’t available by default.
Types of Add-ins:
- Custom Visuals: Imported from AppSource or developed by users. It can include heat maps, word clouds, etc.
- Office Add-ins: Power BI add-ins available in tools like Excel and PowerPoint to embed or analyze Power BI data.
- Third-party Add-ins: External connectors and tools that integrate Power BI with services like Salesforce, Adobe Analytics, etc.
Example:
- Embedding Power BI reports in PowerPoint using the Power BI add-in.
- Importing a Hierarchy Slicer visual from AppSource into Power BI Desktop.
Q. Find Average Sales per Customer.
We can write dax query like:
Avg Sales per Customer =
DIVIDE(
SUM(Sales[Amount]),
DISTINCTCOUNT(Sales[CustomerID])
)
Q. Find Distinct number of Products sold.
We can write dax query like:
Unique Products = DISTINCTCOUNT(Sales[ProductID])
Q. Find Total Employees who joined after 2020.
We can write dax query like:
Employees_After2020 =
CALCULATE(
COUNTROWS(Employee),
Employee[JoiningYear] > 2020
)
Q. Find Year-over-Year (YoY) Growth in Sales.
We can write dax query like:
YoY Sales Growth =
DIVIDE(
[Total Sales] – CALCULATE([Total Sales], SAMEPERIODLASTYEAR(Date[Date])),
CALCULATE([Total Sales], SAMEPERIODLASTYEAR(Date[Date]))
)
Q. Find % of Total Sales by Region.
We can write dax query like:
Sales % by Region =
DIVIDE(
SUM(Sales[Amount]),
CALCULATE(SUM(Sales[Amount]), ALL(Sales[Region]))
)
Q. Find Top 5 Products by Sales in 2023.
Use a Top N filter in the visual:
- Add Product and Total Sales
- Apply Top N = 5 by Sales OR in DAX:
Top5 Products =
TOPN(5, SUMMARIZE(Sales, Sales[Product], “Sales”, SUM(Sales[Amount])), [Sales], DESC)
Q. Your report is very slow because of large data. What steps can you take?
- Reduce data using filters before loading.
- Use Import Mode instead of DirectQuery.
- Remove unnecessary columns.
- Use Aggregations for summary tables.
Q. How to ask Power BI “Show me total sales in 2023” in natural language. How will you do this?
We can use Power Q&A by typing the question directly into the Q&A visual.
Syntax:
total sales in 2023
Q. If we have two tables: Customers and Orders. How do you connect them?
Create a One-to-Many relationship by CustomerID in Customers → CustomerID in Orders.
Syntax:
Customers[CustomerID] 1 → * Orders[CustomerID]
Q. How can you merge two datasets like Online Sales and Store Sales into one?
Use Append Queries in Power Query.
Syntax:
Combined Sales = Append(Online Sales, Store Sales)
Q. You want to add a new column that says “Pass” if marks > 40 else “Fail”. How will you do this?
Use Conditional Column in Power Query with rule: If Marks > 40 → Pass, Else → Fail.
Syntax:
Result = if [Marks] > 40 then “Pass” else “Fail”
Q. How can sales data be summarized by Region and Month. How do you do this?
Use a Matrix visualization with Region as rows, Month as columns and Sales as values.
Syntax:
Rows = Sales[Region]
Columns = Sales[Month]
Values = SUM(Sales[Amount])
Q. How to analyze trends in Sales over time. Which visualization will you use?
Answer: Use a Line Chart with Date on X-axis and Sales on Y-axis.
Q. Make KPI showing whether actual sales met the target. How do you create it?
Create Actual Sales and Target Sales measures, then use a KPI visual to compare.
Syntax:
Actual Sales = SUM(Sales[Amount])
Target Sales = SUM(Targets[TargetAmount])
Q. You need to restrict data visibility so that regional managers only see data for their own region. How will you achieve this?
- Implement Row-Level Security (RLS) in Power BI.
- Define roles in Power BI Desktop (e.g., [Region] = USERPRINCIPALNAME() mapping).
- Publish report to Power BI Service and assign roles to specific users.
