5 Interview Questions in PowerBI.

Join My PowerBI Group.

1)What is the difference between a measure and a calculated column?

2)What is Dax in PowerBI ?

3)How to publish PowerBI report in PowerBI service?

4)What is the difference between PowerBI desktop And PowerBI Service?

5)How to get Data from multiple Sources into PowerBI ?

1)What is the difference between a measure and a calculated column?

In Power BI, measures and calculated columns are both used to perform calculations on data, but they serve different purposes and have distinct characteristics:

1. Calculated Column:A calculated column is a new column that you add to a table in your data model.It is calculated row by row within the table and stored physically in the data model.Calculations are performed during data refresh or when the data is loaded into the model.Calculated columns are useful for creating new fields based on existing data in your dataset.Calculated columns can be used in visualizations like any other column in your dataset.
2. Measure:A measure is a calculation performed on-the-fly when interacting with a visualization in Power BI.Measures are not stored in the underlying data model; they are calculated dynamically based on the context of the visualization or user interaction.Measures are typically created using DAX (Data Analysis Expressions) and can involve aggregations, calculations across different tables, or complex logic.Measures are commonly used for aggregations, such as sums, averages, counts, or complex calculations involving filters and relationships between tables.Measures are particularly useful for creating key performance indicators (KPIs) and for creating dynamic calculations that respond to user interactions, filters, and slicers in reports.

2)What is Dax in PowerBI ?

DAX stands for Data Analysis Expressions. It's a formula language and query language used in Power BI, Excel Power Pivot, and Analysis Services Tabular models. DAX is designed to work with relational data and perform complex calculations, data analysis, and aggregation tasks.

Here are some key points about DAX in Power BI:

1. Formula Language: DAX is used to create formulas and expressions for calculated columns, measures, and calculated tables within Power BI. These formulas can perform calculations, manipulate data, filter data, and define business logic.
2. Data Modeling: DAX is closely tied to the data model in Power BI. It allows users to define relationships between tables, create calculated columns based on data in those tables, and write measures to perform calculations on the data.
3. Aggregation Functions: DAX includes a wide range of functions for performing aggregations, such as SUM, AVERAGE, MIN, MAX, COUNT, and more. These functions can be used to summarize data at different levels of granularity.
4. Time Intelligence: DAX includes functions specifically designed for handling time-based calculations, such as calculating year-to-date totals, moving averages, and comparing values over different time periods.
5. Filtering and Context: DAX expressions are evaluated within the context of a specific filter context. This means that calculations can respond dynamically to filters applied to a report, such as slicers or visual interactions.
6. Performance Optimization: Writing efficient DAX expressions is crucial for maintaining good performance in Power BI reports, especially when dealing with large datasets. Optimizing DAX calculations often involves understanding the underlying data model, leveraging relationships, and using DAX functions effectively.

3)How to publish PowerBI report in PowerBI service?

Publishing a Power BI report to the Power BI service involves several steps. Here's a general guide:

1. Prepare your report: Ensure that your Power BI report is complete and ready for sharing. This includes creating visualizations, adding interactive elements like slicers and filters, and defining any necessary calculations or measures.
2. Save your report: Save your Power BI report file (.pbix) locally on your computer. It's a good idea to organize your files in a way that makes them easy to locate.
3. Sign in to Power BI service: Open your web browser and navigate to the Power BI service (app.powerbi.com). Sign in with your Power BI account credentials. If you don't have an account, you can sign up for a free account.
4. Navigate to your workspace: Once you're signed in, you'll be taken to the Power BI homepage. Navigate to the workspace where you want to publish your report. If you don't have a workspace, you can create one by clicking on "Create" > "Workspace".
5. Upload your report: In the workspace, click on the "Upload" button in the toolbar at the top of the page. Select "File" from the dropdown menu, then browse to the location on your computer where your Power BI report file is saved. Select the file and click "Open" to upload it to the Power BI service.
6. Monitor the upload process: Power BI will begin uploading your report file to the service. Depending on the size of your report and your internet connection speed, this process may take some time. You can monitor the progress of the upload in the status bar at the bottom of the page.
7. Review and publish: Once the upload is complete, you'll see your report listed in the workspace. You can click on the report to open it and review it to ensure that it looks as expected. If everything looks good, click on the "Publish" button in the toolbar to publish the report to the Power BI service.
8. Set permissions (optional): After publishing the report, you can adjust the permissions to control who can view or edit the report. You can share the report with specific users or groups, or make it available to everyone in your organization.
9. Share and collaborate: Once your report is published, you can share it with others by sending them a link or embedding it in a website or application. You can also collaborate with colleagues by allowing them to view or edit the report in the Power BI service.

4)What is the difference between PowerBI desktop And PowerBI Service?

Power BI Desktop and Power BI Service are two components of the Power BI platform, but they serve different purposes and have distinct features. Here's a comparison of the two:

1. Power BI Desktop:Power BI Desktop is a free desktop application that you install on your computer.It is used for creating, designing, and building Power BI reports and dashboards.Power BI Desktop allows you to connect to various data sources, import data, transform and clean data using Power Query Editor, create relationships between tables, define calculations using DAX (Data Analysis Expressions), design visualizations, and create interactive reports.It provides advanced data modeling capabilities, allowing users to create complex data models with multiple tables and relationships.Power BI Desktop is primarily used by report authors and data analysts to develop Power BI content before publishing it to the Power BI service.
2. Power BI Service:Power BI Service is a cloud-based platform provided by Microsoft as part of the Power BI suite.It allows users to publish, share, collaborate on, and consume Power BI reports and dashboards.Power BI Service enables users to access and interact with Power BI content from anywhere using a web browser or mobile device.It provides features for sharing reports with colleagues or stakeholders, setting up data-driven alerts, creating and managing workspaces, scheduling data refreshes, and administering Power BI environments.Power BI Service also includes additional capabilities such as natural language Q&A, AI visuals, and built-in AI capabilities for data exploration and insights.Power BI Service is typically used by report consumers, business users, and administrators for accessing and consuming Power BI content, as well as for collaboration and sharing within organizations.

5)How to get Data from multiple Sources into PowerBI ?

Getting data from multiple sources into Power BI is one of its core functionalities. Here's a general guide on how to do it:

1. Open Power BI Desktop: Launch Power BI Desktop application on your computer.
2. Click on "Get Data": In the Home tab of the Power BI Desktop ribbon, click on the "Get Data" button. This will open a dialog box with various data source options.
3. Select Data Sources: Choose the data sources you want to connect to. Power BI supports a wide range of data sources including databases, files, online services, and more. Some common data sources include:Excel: If your data is in an Excel file (.xlsx or .csv), you can connect directly to it.Databases: You can connect to databases like SQL Server, MySQL, PostgreSQL, Oracle, etc.Online Services: Power BI can connect to various online services like SharePoint, Salesforce, Google Analytics, Azure, etc.Other: Power BI also supports other data sources like web pages, OData feeds, Hadoop files, etc.
4. Connect to Data Source: Once you select the data source, you'll be prompted to provide connection details such as server name, database name, authentication method, etc. Enter the required information and click "Connect" or "OK".
5. Load Data: After connecting to the data source, Power BI will display a navigator window showing the available tables or views from the data source. Select the tables/views you want to import into Power BI and click "Load" or "Transform Data" to proceed.
6. Data Transformation (Optional): Before loading the data into Power BI, you can perform data transformation tasks using the Power Query Editor. This includes cleaning data, filtering rows, removing duplicates, transforming data types, merging tables, adding custom columns, etc.
7. Repeat Steps for Additional Data Sources: If you have data from multiple sources, you can repeat the process by clicking on "Get Data" again and selecting another data source. Power BI allows you to combine data from multiple sources into a single dataset for analysis.
8. Load Data into Power BI: Once you have connected to all the desired data sources and performed any necessary data transformations, click on "Close & Load" to load the data into Power BI. The data will be imported into Power BI and displayed in the Fields pane, ready for analysis and visualization.

PowerBI Course.