200+ Power BI Developer Interview Questions and Answers

The DAX formula for replacing blank values with zero and vice versa is IF(ISBLANK(), 0, BLANK())

• Use the IF function in DAX to check if a value is blank

• If the value is blank, return 0. If not, return blank()

Row-Level Security (RLS) restricts data access for specific users in Power BI reports.

• RLS allows you to control access to data at the row level based on user roles.

• It can be configured using DAX filters in Power BI Desktop under the 'Manage Roles' option.

• Example: Create a role for 'Sales Managers' that only sees data for their respective regions.

• To test RLS, use the 'View as Role' feature in Power BI Desktop to simulate user access.

• RLS can also be implemented in Power BI Serv...read more

Power BI reports can be embedded into SharePoint using the Power BI web part.

• Add the Power BI web part to the SharePoint page

• Enter the URL of the Power BI report in the web part properties

• Configure the web part settings to customize the report display

• Ensure that the SharePoint site and Power BI report are in the same organization

• Use the Power BI service to manage report permissions

Key SQL concepts and DAX functions for Power BI development.

• 1. SQL ORDER OF execution: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY, LIMIT.

• 2. Query for second highest salary: SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees);

• 3. Show duplicate rows: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;

• 4. Calculated columns vs Measure: Calculated columns are computed row by row, while measures are computed o...read more

Row context refers to the current row in a table during DAX calculations, allowing for row-specific evaluations.

• Row context is established when a DAX formula is evaluated for each row in a table.

• An example of a DAX function that allows row context is 'SUMX', which iterates over a table and evaluates an expression for each row.

• In 'SUMX(Table, Expression)', 'Table' provides the row context for 'Expression'.

• Another example is 'FILTER', which can create a row context when applied...read more

Data modeling in Power BI involves structuring data to create meaningful insights and relationships for effective reporting.

• Star Schema: A common modeling technique where a central fact table is connected to multiple dimension tables, e.g., sales data linked to product and customer dimensions.

• Relationships: Establishing relationships between tables using primary and foreign keys, such as linking a 'CustomerID' in a sales table to a 'CustomerID' in a customer details table.

• Dat...read more

Slicers and filters are both used to control data visibility in Power BI, but slicers are visual elements while filters can be applied programmatically.

• Slicers are visual controls that allow users to select values from a predefined list, which filters the data accordingly.

• Filters can be applied programmatically using DAX formulas or Power Query M language.

• Slicers are typically used for interactive data exploration and analysis, while filters are more commonly used for data ma...read more

The ALL DAX function removes filters from a table or column, returning all rows for calculations.

• ALL(TableName): Returns all rows from the specified table. Example: ALL(Sales) returns all sales records.

• ALL(ColumnName): Returns all unique values from the specified column. Example: ALL(Sales[Product]) returns all products.

• ALLSELECTED(TableName): Returns all rows in a table while respecting filters applied in the report. Example: ALLSELECTED(Sales) considers slicers.

• ALLSELECTED(...read more

Automate data handling using Power BI features like data refresh and data modeling.

• Utilize Power BI data refresh feature to automatically update employee data from a data source.

• Implement data modeling in Power BI to organize and analyze the 500 employee data efficiently.

• Leverage Power BI automation tools like Power Query and DAX to streamline data processing tasks.

• Create interactive reports and dashboards in Power BI to visualize and analyze the employee data effectively.

Filters are used to restrict data at the report level, while slicers are interactive visual filters applied to specific visuals.

• Filters are applied at the report level and affect all visuals, while slicers are applied to specific visuals only.

• Slicers allow users to interactively filter data by selecting values from a list or range.

• Filters can be applied to multiple visuals at once, while slicers are applied individually to each visual.

• Slicers provide a more user-friendly way ...read more

Row context refers to the current row in a table, while filter context applies filters to data during calculations.

• Row Context: Represents the current row being evaluated in a table. Example: In a calculated column, each row's values are used.

• Filter Context: Refers to the filters applied to data during calculations, affecting the result of measures. Example: Using slicers.

• Row Context is implicit in calculated columns, while Filter Context is often created by measures and visu...read more

Data modeling is the process of creating a visual representation of data to analyze and make informed decisions. DAX is a formula language in Power BI used for calculations.

• Data modeling involves organizing and structuring data to create relationships between different data sets.

• DAX (Data Analysis Expressions) is a formula language used in Power BI to perform calculations and create custom measures.

• Calculating revenue using DAX involves summing up the product of price and qua...read more

Schedule report export and email to client using Power BI

• Create a Power BI report with the data to be exported

• Set up a data refresh schedule for the report

• Use Power BI subscription feature to email the report to the client

I have worked on various types of data sets including sales data, customer data, financial data, and social media data.

• Sales data

• Customer data

• Financial data

• Social media data

There are three types of gateways in Power BI: On-premises data gateway, Personal gateway, and Power BI Gateway (Enterprise). Each serves a different purpose.

• On-premises data gateway is used to connect on-premises data sources to Power BI service.

• Personal gateway is used for individuals to refresh data from on-premises data sources.

• Power BI Gateway (Enterprise) is used for organizations to manage data refresh for cloud and on-premises data sources.

• Gateways are used to securel...read more

Implement security to data using row-level security (RLS)

• Use user roles and permissions to restrict access to specific data

• Leverage Power BI's built-in security features such as dataset security and data categorization

• Implement dynamic security based on user context or attributes

• Utilize Power BI's security features like Azure Active Directory integration for authentication and authorization

A line graph is typically used to represent historical sales data.

• Line graph is ideal for showing trends over time

• It helps in visualizing the sales performance over different time periods

• Can be used to compare sales data from different years or quarters

Tableau and Power BI are both data visualization tools, but Power BI is more user-friendly and affordable while Tableau is more powerful and flexible.

• Power BI is easier to use and has a lower learning curve

• Tableau has more advanced features and customization options

• Power BI is more affordable for small to medium-sized businesses

• Tableau is better for large enterprises with complex data needs

• Power BI integrates well with other Microsoft products

• Tableau has a larger community an...read more

Measures are dynamic calculations based on the data model, while calculated columns are static calculations added to a table.

• Measures are used in visualizations and change based on filters and slicers

• Calculated columns are added to a table and are not affected by filters or slicers

• Creating a custom table involves defining the columns and their data types, and then populating it with data

• Custom tables can be created using Power Query or DAX formulas

Star schema has a single fact table connected to multiple dimension tables, while snowflake schema has normalized dimension tables.

• Star schema denormalizes dimension tables, making it easier to query but potentially less efficient for storage.

• Snowflake schema normalizes dimension tables, reducing redundancy but potentially making queries more complex.

• Star schema is commonly used for data warehouses with denormalized data, while snowflake schema is used for normalized OLAP sys...read more

Power BI Pro is a user-based license that allows individuals to publish and share reports, while Power BI Premium is a capacity-based license that provides dedicated resources for larger organizations.

• Power BI Pro is a user-based license, while Power BI Premium is a capacity-based license.

• Power BI Pro allows individuals to publish and share reports, while Power BI Premium provides dedicated resources for larger organizations.

• Power BI Pro is suitable for small to medium-sized ...read more

DAX is a formula language used in Power BI for data analysis. Power BI is a business analytics tool for visualizing and sharing insights.

• DAX is used to create custom calculations in Power BI, such as measures and calculated columns.

• DAX functions can be used to manipulate data, perform calculations, and create aggregations.

• Power BI utilizes DAX to create interactive visualizations and reports based on the data model.

• Examples of DAX functions include SUM, AVERAGE, CALCULATE, an...read more

DAX (Data Analysis Expressions) is a formula language used in Power BI for data modeling and analysis.

• DAX is used to create calculated columns and measures in Power BI.

• Common DAX functions include SUM, AVERAGE, COUNT, and FILTER.

• Example: SUM(Sales[Total]) calculates the total sales amount.

• DAX supports time intelligence functions like YEAR, MONTH, and DATEDIFF.

• Example: DATEDIFF(Sales[OrderDate], TODAY(), DAY) calculates the number of days since the order date.

Import model is a Power BI feature that allows you to import data from various sources and create a data model.

• Import model is used to create a data model in Power BI.

• It allows you to import data from various sources such as Excel, CSV, SQL Server, etc.

• You can create relationships between tables, add calculated columns, and measures.

• Import model is useful when you have large amounts of data that need to be transformed and modeled.

• It is also useful when you need to combine dat...read more

Power BI performance optimization techniques enhance report speed and efficiency, ensuring smooth data visualization and analysis.

• Data Model Optimization: Use star schema design to reduce complexity and improve query performance. For example, separate fact and dimension tables.

• Reduce Data Volume: Limit the amount of data loaded into Power BI by filtering unnecessary columns and rows. For instance, use SQL queries to pre-aggregate data.

• Use Aggregations: Implement aggregations ...read more

Role-playing dimensions allow a single dimension to be used in multiple contexts, enhancing data modeling in star schemas.

• Definition: Role-playing dimensions are dimensions that can be used in multiple roles within a data model, such as a 'Date' dimension representing 'Order Date' and 'Ship Date'.

• Star Schema: A star schema organizes data into fact tables and dimension tables, simplifying queries and improving performance.

• Example: In a sales database, a 'Customer' dimension ca...read more

Power BI is a business analytics tool by Microsoft that enables data visualization and sharing insights across organizations.

• Data Connectivity: Power BI connects to various data sources like SQL Server, Excel, and cloud services.

• Data Transformation: Users can clean and transform data using Power Query Editor to prepare it for analysis.

• Interactive Dashboards: Create visually appealing dashboards that provide real-time insights and key performance indicators.

• Custom Visuals: Pow...read more