200+ Power BI Developer Interview Questions and Answers

A published data source is a dataset that has been shared and made accessible to others within an organization.

• Published data sources can be accessed and used by multiple users within an organization.

• They are typically stored in a centralized location for easy access.

• Changes made to a published data source are reflected in all reports that use that data source.

• Examples include shared Excel files, SQL databases, and Power BI datasets.

Extended data sources refer to additional data connections beyond the standard sources in Power BI.

• Extended data sources allow users to connect to a wider range of data sources for analysis.

• Examples of extended data sources include web services, custom APIs, and cloud storage platforms.

• These additional connections enhance the flexibility and capabilities of Power BI for data analysis and visualization.

Time intelligence functions in DAX are used to perform calculations based on dates and times.

• Time intelligence functions help in comparing data over different time periods.

• Functions like TOTALYTD, SAMEPERIODLASTYEAR, and DATESBETWEEN are commonly used for time intelligence.

• They can be used to calculate year-to-date totals, compare values with previous periods, and more.

SSAS cubes can be refreshed using SQL Server Agent jobs, XMLA scripts, or manually through SQL Server Management Studio.

• SSAS cubes can be refreshed using SQL Server Agent jobs scheduled at specific intervals.

• XMLA scripts can be used to automate the process of refreshing SSAS cubes.

• Manual refreshing of SSAS cubes can be done through SQL Server Management Studio by processing the cube.

• Refreshing can also be triggered programmatically using tools like PowerShell scripts.

Power BI supports multiple connectivity modes for data sources.

• DirectQuery mode allows real-time data access from the source system.

• Import mode imports data into Power BI for faster performance.

• Live Connection mode connects to an external Analysis Services model.

• Power BI Gateway enables on-premises data access.

• Power BI Dataflows allows data preparation and transformation in the cloud.

Calculated columns are columns created in Power BI by using DAX formulas, while measures are calculations based on the data model.

• Calculated columns are static and stored in the data model, while measures are dynamic and calculated on the fly.

• Calculated columns are used for adding new data to a table, while measures are used for aggregating data or performing calculations.

• Examples of calculated columns include adding a new column for profit margin, while measures can be used ...read more

RLS stands for Row-Level Security, a feature in Power BI that restricts data access based on user roles.

• RLS allows you to control which rows of data a user can access in a Power BI report or dashboard

• You can define security roles and rules to filter data based on user attributes or roles

• RLS helps in ensuring data privacy and compliance with regulations

• For example, you can use RLS to restrict a sales manager to only see data related to their region

I am proficient in programming languages such as SQL, DAX, Python, and R.

• SQL

• DAX

• Python

• R

Power BI Report is a single report page, while Power BI App is a collection of multiple reports and dashboards.

• Power BI Report is a single page report with visualizations and data insights.

• Power BI App is a collection of multiple reports, dashboards, and datasets organized together.

• Power BI Report can be shared individually, while Power BI App is shared as a package of related content.

• Power BI App allows for more interactive and customized user experience compared to a single...read more

End users can access the report through Power BI Service, Power BI Mobile App, or embedded in other applications.

• End users can access the report through Power BI Service by logging in with their credentials

• End users can also access the report through Power BI Mobile App on their smartphones or tablets

• Reports can be embedded in other applications using Power BI Embedded feature

ROS stands for Return on Sales in Power BI.

• ROS is a financial metric used to measure the profitability of a company.

• It is calculated by dividing the net income by the total revenue.

• ROS is expressed as a percentage and is used to evaluate a company's efficiency in generating profits.

• For example, if a company has a net income of $100,000 and total revenue of $1,000,000, the ROS would be 10%.

Power BI offers three storage modes: Import, DirectQuery, and Composite, each serving different data handling needs.

• Import Mode: Data is imported into Power BI, allowing for fast performance and rich data modeling. Example: Loading sales data from Excel.

• DirectQuery Mode: Data remains in the source system, allowing real-time queries. Example: Connecting to a SQL Server database for live data.

• Composite Mode: Combines both Import and DirectQuery, enabling flexibility in data sou...read more

Power BI components include Power Query, Power Pivot, Power View, Power Map, and Power Q&A.

• Power Query: Used for data extraction and transformation.

• Power Pivot: Used for data modeling and analysis.

• Power View: Used for interactive data visualization.

• Power Map: Used for geographical data visualization.

• Power Q&A: Allows users to ask questions in natural language and get answers from data.

Relationships in Power BI define how different tables are connected to each other.

• Relationships define how tables are related to each other based on common fields

• They are used to create connections between tables for data analysis

• Relationships can be one-to-one, one-to-many, or many-to-many

• They are essential for creating accurate and meaningful visualizations in Power BI

The extension of Tableau files is .twb for Tableau Workbook files and .twbx for Tableau Packaged Workbook files.

• .twb files are Tableau Workbook files which contain references to data sources and visualizations

• .twbx files are Tableau Packaged Workbook files which include the data sources and visualizations within the file itself

• Both file types can be opened and edited in Tableau Desktop

Use data modeling techniques, optimize data sources, and leverage Power BI features like aggregations and incremental refresh.

• Utilize data modeling techniques like creating relationships, hierarchies, and calculated columns to optimize data.

• Optimize data sources by using query folding, reducing unnecessary columns, and filtering data before loading into Power BI.

• Leverage Power BI features like aggregations to pre-calculate summarized data for faster query performance.

• Implemen...read more

DAX is a formula language used in Power BI for creating custom calculations and measures.

• DAX stands for Data Analysis Expressions

• It is used to create custom calculations, measures, and columns in Power BI

• DAX functions can be used to perform calculations, manipulate data, and create complex formulas

• Measures are calculations that are created using DAX and are used for aggregating data in Power BI reports

• Calculations in DAX can include functions like SUM, AVERAGE, COUNT, etc.

I have extensive experience with SQL and ADF

• Proficient in writing complex SQL queries for data extraction, transformation, and loading

• Experience in designing and implementing data pipelines using Azure Data Factory (ADF)

• Familiar with scheduling and monitoring data pipelines in ADF

• Worked on integrating SQL databases with ADF for seamless data flow

Types of context refer to the different ways in which data can be analyzed and interpreted in Power BI.

• Row context: evaluates calculations row by row

• Filter context: applies filters to data before calculations

• Query context: used in DAX queries to retrieve data

• Relationship context: determines how tables are related

Power Query is used for data transformation and Power View is used for data visualization in Power BI.

• Power Query is used to extract, transform, and load data from different sources.

• Power View is used to create interactive visualizations and reports based on the transformed data.

• Power Query is more focused on data preparation and cleaning, while Power View is focused on data visualization.

• Power Query can be used to merge, append, and transform data before visualizing it in Po...read more

Use SQL query with ORDER BY and LIMIT to find the 4th highest salary

• Use ORDER BY clause to sort salaries in descending order

• Use LIMIT 3,1 to skip the first 3 highest salaries and get the 4th highest salary

A gateway in Power BI is a bridge that connects on-premises data sources to the cloud service.

• There are two types of gateways in Power BI: On-premises data gateway and Personal gateway.

• On-premises data gateway is used to connect cloud services to on-premises data sources.

• Personal gateway is used for individual users to refresh data within Power BI.

• Gateways ensure secure data transfer between on-premises and cloud environments.

Power BI is a business analytics tool that provides interactive visualizations and business intelligence capabilities.

• Power BI is a Microsoft product used for data analysis and visualization.

• It allows users to connect to various data sources and create interactive reports and dashboards.

• Power BI provides a wide range of visualizations, such as charts, maps, and tables, to represent data.

• Users can create custom calculations, measures, and hierarchies to analyze data in differe...read more

Drill down and drill through are interactive features in Power BI that allow users to explore data in more detail.

• Drill down allows users to navigate from a higher level of data to a more detailed level by clicking on a visual element, such as a bar chart or table.

• Drill through allows users to access a more detailed report or page by clicking on a specific data point within a visual element.

• Both features provide users with the ability to analyze data in a more granular way an...read more

I prefer not to disclose my current CTC.

• I believe that my current salary is not relevant to my qualifications and experience for this position.

• I am more interested in discussing the salary range for this role and how my skills and experience align with the requirements.

• I am open to negotiation based on the overall compensation package offered.

Data Gateway can be installed in Power BI by downloading and running the installer.

• Download the Data Gateway installer from the Power BI service

• Run the installer and follow the installation wizard

• Sign in with your Power BI account to register the gateway

Normalization is a database design technique that organizes data in a structured manner to eliminate redundancy and improve data integrity.

• Normalization helps in reducing data redundancy by breaking down a large table into smaller, more manageable tables.

• There are different normal forms, such as 1NF, 2NF, 3NF, BCNF, and 4NF, each with specific rules and dependencies.

• Normalization ensures data integrity by minimizing data anomalies, such as update, insert, and delete anomalies...read more

A pipeline in data engineering is a sequence of data processing steps that transform raw data into a usable format.

• A pipeline is a set of interconnected data processing components.

• It involves extracting, transforming, and loading (ETL) data.

• Pipelines can be used for data integration, data migration, or data transformation tasks.

• They ensure data quality, consistency, and reliability.

• Examples of data engineering pipelines include extracting data from multiple sources, cleaning ...read more

There are multiple types of filters in Power BI including visual, page, report, and drill-through filters.

• Visual filters apply to a specific visual or group of visuals.

• Page filters apply to all visuals on a specific page.

• Report filters apply to all visuals on all pages of a report.

• Drill-through filters allow users to navigate to a different report page based on a selected data point.

Many to many relationships can be handled using bridge tables or DAX functions in Power BI.

• Create a bridge table to connect the two tables with a many to many relationship

• Use DAX functions like CROSSFILTER or USERELATIONSHIP to handle many to many relationships

• Consider using bidirectional filtering to handle many to many relationships

Coalesce function returns the first non-null value from a list of values.

• Coalesce function is used in SQL and other programming languages.

• It takes two or more arguments and returns the first non-null value.

• If all arguments are null, it returns null.

• Example: COALESCE(NULL, 'hello', NULL, 'world') returns 'hello'.

Write a DAX query in data modeling

• Use CALCULATE function to apply filters and context to calculations

• Use SUMX function to iterate over a table and perform calculations

• Use RELATED function to retrieve related values from other tables

Power Pivot is a data modeling tool in Excel and Power BI that allows users to create complex data models and perform advanced analysis.

• Power Pivot is an add-in for Excel and Power BI

• It allows users to create data models with multiple tables and relationships

• Users can perform advanced calculations and analysis using DAX formulas

• Power Pivot can handle large amounts of data and improve performance

• It is a powerful tool for business intelligence and data analysis

Numerical range parameter is a parameter that defines a range of numerical values for a specific variable or function.

• It is used to specify a range of numerical values that a parameter can take.

• It helps in filtering data based on a specific numerical range.

• For example, a numerical range parameter can be used to filter sales data for products with prices between $50 and $100.

Power BI Premium offers dedicated capacity and advanced features, while Power BI Pro is a subscription-based service for individual users.

• Power BI Premium provides dedicated capacity for larger organizations and advanced features like AI capabilities and paginated reports.

• Power BI Pro is a subscription-based service for individual users and small to medium-sized businesses.

• Power BI Premium allows for larger data volumes and faster refresh rates compared to Power BI Pro.

• Power ...read more

Power BI software is used for data visualization and analysis.

• Allows for easy creation of interactive reports and dashboards

• Provides real-time data insights

• Integrates with various data sources

• Enables collaboration and sharing of reports

• Helps in making data-driven decisions

Calculated columns are static values calculated at row level, while measures are dynamic aggregations calculated at query time.

• Calculated columns are stored in the data model and can be used in visuals directly.

• Measures are not stored in the data model and are calculated on the fly based on the context of the visualization.

• Calculated columns are useful for creating new columns based on existing data, while measures are used for aggregations like sum, average, etc.

Relationship cardinality defines the number of instances of one entity that can be associated with the number of instances of another entity.

• One-to-One: Each record in the first entity is associated with only one record in the second entity.

• One-to-Many: Each record in the first entity can be associated with multiple records in the second entity.

• Many-to-Many: Multiple records in the first entity can be associated with multiple records in the second entity.

Show all filter is a feature in Power BI that allows users to display all values in a filter, including those that are not currently selected.

• Show all filter is used to display all values in a filter, even if they are not selected.

• It can be helpful when users want to see all available options in a filter.

• Users can choose to show all values or only selected values in a filter.

INNER JOIN is used to combine rows from two or more tables based on a related column between them.

• Use INNER JOIN to retrieve rows from both tables that have matching values in the specified column

• Syntax: SELECT column_name(s) FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name

• Example: SELECT Orders.OrderID, Customers.CustomerName FROM Orders INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID

Duplicates are identical copies of data, while references are pointers to the same data in memory.

• Duplicates are exact copies of the original data.

• References point to the same data in memory.

• Duplicates can lead to inconsistencies in data analysis.

• References are more memory efficient than duplicates.

There are three connectivity modes in Power BI: Import, DirectQuery, and Live Connection.

• Import mode: Data is imported into Power BI and stored in a dataset.

• DirectQuery mode: Data stays in the data source and queries are sent directly to the source.

• Live Connection mode: Power BI connects directly to the data source for real-time data access.

Clustered Gateway is a feature in Power BI that allows multiple gateway instances to be clustered together for high availability and load balancing.

• Clustered Gateway allows multiple gateway instances to be grouped together to provide high availability and load balancing.

• It helps in distributing the data refresh and query processing workload across multiple gateway instances.

• Clustered Gateway ensures that if one gateway instance fails, another instance can take over to ensure ...read more

Gateway connection in Power BI allows on-premises data sources to be accessed securely.

• Install and configure an on-premises data gateway on the server where the data source is located.

• Create a data source in Power BI and select 'On-premises data gateway' as the connection mode.

• Specify the gateway and credentials to establish a secure connection.

• Ensure the gateway is running and connected to the Power BI service for data refresh and access.

Sum calculates the total of a column, while SumX calculates the total of an expression evaluated for each row.

• Sum is used to calculate the total of a column in a table.

• SumX is used to calculate the total of an expression evaluated for each row in a table.

• SumX is often used in DAX formulas to perform calculations on a row-by-row basis.

• For example, Sum([SalesAmount]) would calculate the total sales amount, while SumX(Sales, [SalesAmount]*[Quantity]) would calculate the total sa...read more

Append in Power Query is used to combine multiple tables or queries into a single table or query.

• Append is used to stack tables on top of each other, adding rows from one table to the end of another.

• It is useful when you have multiple tables with the same structure and want to combine them into one.

• You can append tables from different data sources or within the same data source.

• For example, you can append sales data from different regions into a single table for analysis.

Merge in Power Query combines multiple tables into one by matching rows based on specified columns.

• Merge is used to combine tables in Power Query

• You can merge based on one or more columns

• Different types of merges include inner, left outer, right outer, and full outer joins