How to Prepare for a Power BI Interview

Power BI is a Business Intelligence tool developed by Microsoft in 2013 that blends several add-ons of Excel to build a new and completely independent BI tool. Once you have established reports using Power Query, Power Pivot, and Power View, you can discuss your comprehensions with your colleagues. This is where Power BI enters the equation. Power BI allows you to load Excel workbooks into the cloud and share them with a chosen group of co-operatives.

The demand for specialists skilled in this tool has grown rapidly in recent years. Whether you’ve already begun a career in business intelligence, data analysis, ETL and data warehousing, or another data-driven area, or you just want to add to your job skills in the business world, getting a Power BI certification is a smart step. This blog isn’t a full Power BI tutorial, it will help you to brush up with the Power BI basics and aims to prepare you for Power BI related job roles in major companies that offer great salaries. Skim through these popular Power BI interview topics and prepare yourself for the job interview:

Building Blocks in Power BI

The following are the Building Blocks (or) key components of Power BI:

  1. Visualizations: Visualization is a visual representation of data.
    Example: Pie Chart, Line Graph, Side by Side Bar Charts, TreeMap, etc.
  2. Datasets: Dataset is a collection of data that Power BI uses to create its visualizations.
    Example: Excel sheets, Oracle, or SQL server tables.
  3. Reports: A Report is a collection of visualizations that appear together on one or more pages.
    Example: Sales by Country, State, City Report, Logistic Performance report, Profit by Products report, etc.
  4. Dashboards: A dashboard is a single-layer presentation of multiple visualizations, i.e. we can incorporate one or more visualizations into a one-page layer.
    Eg: The sales dashboard can have pie charts, geographical maps, and bar charts.
  5. Tiles: Tile is a single visualization in a report or on a dashboard.
    Eg: Pie Chart in Dashboard or Report.

Main components of the Power BI toolkit

  • Power Query: Power Query is the data connectivity and data preparation technology that enables end-users to seamlessly import and reshape data from within a wide range of Microsoft products, including Excel, Power BI, Analysis Services, Data verse, and more.
  • Power Pivot: Power Pivot is an add-in for Microsoft Excel 2010 that enables you to import millions of rows of data from multiple data sources into a single Excel workbook. It lets you generate connections between heterogeneous data, creates calculated columns and measures using formulas, build PivotTables and Pivot Charts. You can then further scrutinize the data so that you can make timely business decisions without looking for IT assistance.
  • Power Map: Power Map is an Excel add-in that provides you with a powerful set of tools to help you visualize and gain insight into large sets of data that have a geo-coded component. It can help you generate 3D visualizations in the form of column, heat, and bubble maps on top of a Bing map.

Content Packs in Power BI

Content packs for services are pre-built solutions for popular services as part of the Power BI experience. A subscriber to a supported service can quickly connect to their account from Power BI to see their data through live dashboards and interactive reports that have been pre-built for them. Organizational content packs provide users, BI professionals, and system integrator the tools to build their own content packs to share purpose-built dashboards, reports, and datasets within their organization.

Data Analysis Expression (DAX)

DAX (Data Analysis Expressions) is a formula expression language and can be used in different BI and visualization tools. DAX is also known as function language, where the full code is kept inside a function. DAX programming formula contains two data types: Numeric and Other. Numeric includes – integers, currency and decimals, while Other includes: string and binary object.

Fundamental Concepts of DAX

Ø  Syntax

This is how the formula is written—that is, the elements that comprise it. The Syntax includes functions such as SUM (used when you want to add figures). If the syntax is not correct, you will get an error message.

Ø  Functions

These are formulas that use specific values (also known as arguments) in a certain order to perform a calculation, similar to the functions in Excel. The categories of functions are date/time, time intelligence, logical, information, mathematical, text, statistical, parent/child, and others.

Ø  Context

There are two types: row context and filter context. Whenever a formula has a function that applies filters to identify a single row in a table, row context comes into action. When one or more filters are applied in a calculation that determines a result or value, the filter context takes over.

 

Common DAX Functions

  • Aggregate Functions: MIN, MAX, Average, SUM, SUMX
  • Counting Functions: DISTINCTCOUNT, COUNT, COUNTA, COUNTROWS, COUNTBLANK
  • Logical Functions: And, OR, NOT, IF, IFERROR
  • Text Functions: REPLACE, SEARCH, UPPER, FIXED, CONACATENATE
  • Date Functions: DATE, HOUR, WEEKDAY, NOW, EOMONTH
  • Information Functions: ISBLANK, ISNUMBER, ISTEXT, ISNOTEXT, ISERROR

Power BI vs. Tableau

Microsoft Power BI and Tableau are both data analytics tools. Power BI has an extensive free version as well as a premium paid version, while Tableau’s free version has limited capabilities. Power BI is considered more intuitive to use than Tableau, as some features in Tableau are hidden behind menus, which makes it harder to learn and use. Power BI has a natural-language query tool, which Tableau doesn’t. Overall, however, Tableau may offer more capabilities for those who are experienced in data analytics. So, for the question of Power BI vs. Tableau, Microsoft Power BI is generally considered better for those new to data analytics, especially if they already have experience in Microsoft products such as Excel, Azure, and Office 365.

I hope this set of Power BI Interview topics will help you in preparing for your interviews. To learn more answers and get a career-boosting Power BI certification, sign up for Power BI certification training course today! This training will help you understand Power BI indepth and help you achieve mastery over the subject. Be yourself, show your values, make sure you are showing your real intentions for this opportunity and more important than everything, BE CONFIDENT!

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