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Interview Questions and Answers

List of most frequently asked Power BI interview questions and answers for interview preparation.

1- What is Power BI?

Power BI is a very powerful Data Visualization and Business Analytics tool provided by Microsoft. It help us to provide interactive Visualizations, Dashboard & BI Reports with self-service capabilities.

2- Power BI components?

Power BI Desktop, Power BI Gateway, Power BI Mobile Apps, Power BI Service

3- Power BI Building Blocks?

Visualizations, Datasets, Reports, Dashboards, Tiles

4- Power BI supported DataSource

  1. File: Excel, Text/CSV, XML, JSON, PDF etc.
  2. Database: SQL Server, Oracle, MySQL, PostgreSQL, SAP HANA etc.
  3. Azure: Azure SQL, Azure SQL Data warehouse, Azure Blob Storage etc.




5- Data Type in Power BI?

  1. Number type: Decimal Number, Fixed Decimal Number, Whole Number
  2. Date/time types: Date/Time, Date, Time, Date/Time/Timezone, Duration
  3. Text type: Text
  4. Binary type: True/false

6- What is a Report?

The Report is a Power BI feature which is a result of visualized data from a single data set. A report can have multiple pages of visualization.

7- What is a Dashboard?

The Dashboard is used to visualize the strategic data of one or multiple reports in a glance.

8- Measures Vs Quick Measures

Measures: In Power BI Desktop you can create your own measures to using Data Analysis Expressions (DAX) formula language to perform Aggregation level of Calculations such as COUNTS, AVERAGE, SUM, MAX, MIN & many more.

Quick measures are pre-built or you can say readymade measures. You don’t have to write DAX formula for this, it’s done for you based on input you provide in a quick measure dialog box.

9- Bookmarks in Power BI?

Bookmarks capture the present configured view of a report page, including filters, slicers, and the state of visuals. When you select a bookmark, Power BI takes you back to that view.

There are two types of bookmarks – those you create yourself and those created by report designers.

10- Slicers in Power BI?

Slicer is a canvas visual filters. It is used to sort or filter visuals data according to user selection.

11- DAX in Power BI?

DAX stands for Data Analysis Expressions. It is a library of functions and operators to using them we can build formulas and expressions.

12- Power BI Data Connectivity mode?

  1. Direct Query mode
  2. Import mode

13- Difference between SUM() and  SUMX() ?

SUM is a simple aggregation function. It summarizes a value based on a filter context.

Syntax:SUM(<ColumnName>)

SUMX() is an iterator function. Returns the sum of an expression evaluated for each row in a table.

Syntax:SUMX(<table>, <expression>)

Read more

14- Difference between COUNT() and COUNTX() ?

The COUNT function counts the number of cells in a column that contain non-blank values.

Syntax: COUNT(<column>)

The COUNTX function counts only values, dates, or strings. If the function finds no rows to count, it returns a blank.

Syntax: COUNTX(<Table>, <Expression>)

Read more



15- Types of Power BI Filters?

  1. Visual level Filters: This is visual level filter and applied directly on individual visualizations. Such filters are applied both on data and calculation conditions used within a visualization.
  2. Page level Filters: Power BI Page level Filters are used to filter the visuals present in the page.
  3. Report level Filters: The report-level filters are the filters that you use to apply a filter condition on the entire report.
  4. Drillthrough level filter: Drillthrough allows users to navigate to different report pages within a report.

16- What is Power BI Tooltips?

Tooltips  is very cool feature of Power Bi Desktop, it help us to explore our visuals more deeper and it is very easy to use. Tooltips appears when the cursor is hovering over a visual.

17- What is Power BI Cross-report?

Cross-report drill through is a feature in Power BI that enables users to drill through from the data of one report to another separate report

18- Types of DAX functions in Power BI?

  1. Aggregate DAX functions: MIN, MAX, Average, SUM, SUMX
  2. Counting Functions: DISTINCTCOUNT, COUNT, COUNTA, COUNTROWS, COUNTBLANK
  3. Logical Functions: AND, OR, NOT, IF, IFERROR
  4. TEXT Functions: REPLACE, SEARCH, UPPER, FIXED, CONCATENATE
  5. DATE Functions: DATE, HOUR, WEEKDAY, NOW, EOMONTH

Read more

19- Power BI Report Performance technique

  1. Limit the number of visuals in dashboards and reports.
  2. To improve Power BI report performance, remove unnecessary interactions between visuals, by default it is enable.
  3. Use Microsoft AppSource certified custom visuals where applicable.
  4. If possible avoid to use hierarchical filters
  5. Remove unused tables or columns from dataset, where possible.
  6. Use integers instead of strings, where possible.
  7. Used Performance analyzer, This new tool lets you analyze the speed of your dashboard and will point out the bottlenecks.

20- What is Edit Interactions in Power BI?

Power BI provides you to very cool features of visual Interaction, by default this feature is enable, that’s means when you select any slicer value or click any visual by default all visuals get filtered on the basis of click or select value. And we can control this feature to using Edit Interactions.

21- What is Power Pivot?

Power Pivot is the component where you can setup a relationship between Tables/Queries loaded into the data model.

It is calculation engine of Power BI. It is used to model complex business data, calculate data that needs to be displayed in the area of the value field in the Pivot charts/tables.

You can use the Data Analysis Expression (DAX) language to inform the Power Pivot about the various calculations you require.

22- What is Power View?

With the help of Power view, you can create interactive charts, graph, maps and other visuals.

23- What is Power Query?

It is ETL component that helps us to extract, transform and load the data into Power BI desktop. With Power Query you can extract data from multiple data sources like(databases, files, web pages, Azure etc.)

24- Name some Commonly used tasks in the query editor?

  1. Connect to data
  2. Shape and combine data
  3. Group rows
  4. Pivot columns
  5. Create custom columns
  6. Query formulas

25- What is data size in power BI?

The file size limit is 1GB in PRO and 10GB for premium members/users.

26- How many records we are able to see in your Power BI desktop?

1 Million

27. What are the difference sources that you worked on?

Excel, SQL Server, CSV Files, JSON file and Azure SQL Server.

28. Can we delete datasets in pro from works space?

Yes

29- What is Relationship? How many types of relationship?

When you import multiple tables, you are going to analysis data using those tables.

Relationship between those table are necessary in order to accurate calculate result and display the correct information in your reports.

Power BI desktop makes creating those relationships easy. The auto detect feature can do it for you. If you query two or more table at the sometime, when the data is loaded, power bi desktop attempts to find and create relationship for you.

Cardinality, cross filter direction and active properties are automatically set.

Types of Relationships

Active Relationship:  This means the relationship service as the active, default relationship. Where there is more than one relationship provides a way of power bi desktop to automatically create visualizations that include both table.

In-active Relationship:  Suppose you have two tables, 1- Sales Table, 2- Date Table, under Sales table that has two columns Order Date & Ship Date and in Date table there is one Date column.

Suppose you created Relationship between Date table date column with Sales Table Order Date & Ship Date columns.

So in that scenario at a time one relationship will be active and second will be Inactive that is called In active relationship.



30- What is Cardinality?

The cardinality of the relationship means having unique or multiple instances per value for the joining field between two tables.
Cardinality defined by the relationship. Cardinality refers to the relationship between two tables.

  • Many to one (*:1): A many-to-one relationship means, the column in a given table can have more than one instance of a value, and the other related table has only one instance of a value.
  • One to many (1:*): In a one-to-many relationship, the column in one table has only one instance of a particular value, and the other related table can have more than one instance of a value.
  • One-to-one (1:1): In a one-to-one relationship, the column in one table has only one instance of a particular value, and the other related table has only one instance of a particular value.
  • Many to many (*:*): With composite models, you can establish a many-to-many relationship between tables, which removes requirements for unique values in tables.

31- What type saving power BI file?

Power BI file format is. pbix

32. How many types of joins in power BI?

Right Join,  Left Join, Inner Join, Full outer Join

33- What is Button?

The Buttons are used to pop-up of multiple pages in a report.

34- What is Custom Sort?

Custom sort allows you to define a specific order for displaying data. It is an easy way to predefine your own order for displaying data.

35- Can we delete datasets in pro from works space?

Yes

36- Can we create a dashboard from visuals from multiple pages within the report?

Yes, we can create a dashboard from multiple pages .

37- Can we create a dashboard from visuals from multiple reports?

Yes, we can create a dashboard from visuals from multiple reports.

38- Can we create reports in service?

Yes, we can create reports in service.

39- Can we create Calculated columns and measures in Service?

No, we cannot create calculated columns and measures in service

40- Using the username() or userprincipalname() DAX function?

username() will return a user in the format of DOMAIN\User. userprincipalname() will return a user in the format of user@abc.com.

In Power BI service, username() and userprincipalname() will both return the user’s User Principal Name (UPN). This looks similar to an email address.



41- What is RLS?

Row level security is the ability to filter content based on a user’s role. Both Direct Query and data imported to the model support RLS

42- Can we use RLS to limit the columns or measures accessible by my users?

No. If a user has access to a particular row of data, they can see all the columns of data for that row.

43- Does RLS let me hide detailed data but give access to data summarized in visuals?

No, you secure individual rows of data but users can always see either the details or the summarized data.

44- What is Static RLS?

Static RLS is simple, It is used when there is a requirement to restrict a specific user group to see the only same part of the data.

For example, you may want to restrict INDIA salespeople to only view INDIA data.

Power BI Desktop > Test Roles in Desktop Publish to Power BI Service > Add Users to Power BI Service

45- What is Dynamic RLS?

Static RLS is about creating roles manually, If we have too many Roles to create Static RLS is not an option. Thus comes the Dynamic RLS.

Example: if you want to restrict the user based on the state then we need to create Role for each state.

46- Can we delete datasets in pro from works space?

Yes

47- Can we create a dashboard from visuals from multiple pages within the report?

Yes, we can create a dashboard from multiple pages .

48- Can we create a dashboard from visuals from multiple reports?

Yes we can create a dashboard from visuals from multiple reports.

49- Can we create reports in service?

Yes we can create reports in service.

50- Can we create Calculated columns and measures in Service?

No, we cannot create calculated columns and measures in service.



51- Types of Views in Power BI?

  • Report or Canvas view: Allows you to create & view the visualizations.
  • Data view: You can see your all report data here, and you can quickly validate your data.
  • Model view : Shows all of the tables, columns, and relationships in your model and you can set and mange the relationship between tables.

52- What is Custom visual in Power BI?

Custom Visual are not inbuilt Power BI visuals and they are not available in BI desktop. Custom visuals provides advanced level of customization in terms of design & layout. You can import these visuals from Power BI App source.

53- What are the gateways that available in Power BI?

  1. On-premises data gateway(personal mode)
  2. On-premises data gateway( recommended/ standard)

54- What is z-order in Power BI?

Z-order is just a design strategy which is used for arranging visual over shapes. “Z order” refers to the front-to-back alignment of visuals in a report. There is no specific “Z order” button in Power BI.

55- What is Tab Order?

Tab order is the order in which users interact with the items on a page using the keyboard.

56- Explain “M language” in Power BI?

This is the programming language used in Power Query.
It’s a functional, case-sensitive language that’s similar to other programming languages and easy to use.

57- Calculated column in Power BI?

Calculated column is same like other columns in Power BI, it stored in Power BI memory & perform the calculations rows by row.

58- What is Power BI Q&A?

Using Power BI Q&A visual, you can search for your data or discover insights by entering queries in natural language. It instantly understands your query and returns relevant results.

59- What is Content packs in Power BI?

Content packs provide a way to share Power BI objects, such as reports, datasets, or dashboards with individuals within your organization.

60- Apps in Power BI?

An app is a Power BI content type that combines related dashboards and reports, all in one place. An app can have one or more dashboards and one or more reports, all bundled together.

61- What is the incremental refresh?

Incremental refresh help us to load only newly added data instead of entire dataset each time, and now  it is available for Power BI Pro, Premium, and shared subscriptions and datasets.

62- Query folding in Power BI?

Query folding is the ability for a Power Query query to generate a single query statement to retrieve and transform source data.

It is useful in – Incremental Refresh, Import mode & DirectQuery and Dual storage mode tables.

63- Roles in workspace?

Admin

  • Create, edit, delete, copy and publish reports and content in a workspace
  • Publish, Update, or Share App in workspace.
  • Access, view and interact with reports and dashboards in a workspace.
  • Configure and modify Schedule data refreshes and Gateway.
  • Add or Remove other users including other admins.

Member

  • Can all the tasks that are associated with admins but can not add or remove users.
  • Can’t delete the workspace.
  • Can add other users to the viewer or contributor role.

Contributor

  • Can create, edit, delete, copy and publish content and reports within a workspace.
  • Cannot publish, update, or edit an app in a workspace unless given this ability by admins or members.
  • Cannot add or remove users.
  • Modify Gateway and schedule data refreshes.

Viewer

  • Can only view a report or dashboard in a workspace, also can interact with visuals.
  • Cannot add or remove users.
  • Can read data that is stored in workspace dataflows.

64- Import mode vs Direct query mode

In import mode Power BI Desktop store the data inside Power BI Cache. Import mode is very fast compare to Direct Query mode because all data comes from Power BI Desktop Cache.

Direct Query in Power BI is a Data connectivity mode allows you to Direct Connection with live data base. It does not load or copied data into Power BI model, because data directly came from data source.

65- Composite model in Power BI

model that combines data from more than one DirectQuery source or that combines DirectQuery with import data is called a composite model.

66- Index in Power BI?

You can add a Serial number or Row Number column in Power BI.

  • From 0 – It adds index starting from 0.
  • From 1 – It adds index starting from 1.
  • Custom – It gives you ability to set index starting number and increment.

67- What is Gateway?

Gateway is an application and it provides the connection between Power BI cloud services and the data source located on-premises.

Using gateway you can schedule refresh the datasets on cloud. You can installed this application on any servers in the local domain.

68- What is On-premises data gateway (personal mode)?

Only you can use this, and you can use it only for scheduling refresh in Power BI and It can be used only with Power BI service.



69- What is On-premises data gateway(recommended/ standard) mode?

This gateway can be used by multiple users that have access to the server onto which you install the gateway. It can be used for both scheduling refresh and live queries in Power BI.

You can also use it for Power BI, PowerApps, Azure Logic Apps, Power Automate, Azure Analysis Services, dataflows.

 

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