How to Learn Power BI to Crack Data Analysts Interviews

Power BI is a hot topic in the Data Analytics industry right now. 

Being in this industry for 9+ years, let me tell you that Power BI is “the tool”.

It is excellent for visualising and analysing data, and it has become a top choice for Data Analysts worldwide.

Learning Power BI can be a game changer for your career and help you become a competitive candidate in the job market.

In this article, we’ll explore,

• Expectations/ job description of a Data Analyst in detail
• Power BI - Applications
• Components of Power BI
• Power BI vs Tableau
• DAX and its importance
• Steps to learn Power BI

Let’s start with understanding the job responsibilities of a Data Analyst using Power BI.

What are the expectations from a Data Analyst/ Data Visualisation role?

🔷 Data Sources Used

When entering the field of Data Analytics, it's important to have knowledge of multiple data sources.

SQL, Excel files, SharePoint, and OneDrive are common data sources. 

But when it comes to dealing with more advanced data sources, such as those containing images, audio, or text, it's important to have a good understanding of the different data sources available.

There are also certain tools which will allow you to connect with data sources. 

Let's say you are using SAP as your data source for a cloud solution you’re working on, you should at least understand the data that's stored in these SAP tables or SAP database.

And learn how to bring those tables into Power BI or any other tool you're using for ETL operations or visualisation.

You don't need to be a master of that particular source, but you should know how to bring the data from that source to your tool.

When you are targeting good companies explore more data sources and try to get their data.

For instance, try to get data from the web and put it into Power BI.

🔷 Database Knowledge

When it comes to databases, they can be either relational or non-relational in structure. 

Whatever it is, the concern is how the data is stored in that particular database. 

Whether it's on Google Cloud, AWS, or somewhere else, you just need to understand how the data is stored, their structure and how you can replicate that in Power BI.

🔷 Data Connectivity Modes

In Power BI, you can put 10 GB files maximum (1 GB limit for each file size) under the Pro licence.

However, you can add any number of data by using the proper connectivity mode.

There are four different data connectivity modes in Power BI, these are,

• Live Connection:
• Direct Query:
• Import Mode:
• Composite Mode:

For instance, if you have a data size of 100 GB you'll need to use Direct Connectivity mode. 

However, if the data consists of transaction tables only, you can use Direct Connectivity mode for those and use Import mode for other tables of smaller sizes, such as 20 KB, 5 MB, or 10 MB.

Each mode has its limitations and advantages so it's important to choose the one that best suits your needs based on your data size, refresh requirements, and data source location.

🔷 Scripting Languages - SQL and/or Python

Whether you are going for a Data Analytics or Data Visualisation interview, along with Power BI or any visualisation tool, you also need to have a good knowledge of SQL or Python.

SQL and Python are still highly relevant and used in almost every industry.

When you are entering this field or learning something new, you have to be mindful of what’s currently in demand and getting widely used. 

Make sure to include SQL and Python in your resume to demonstrate your proficiency in these languages.

🔷 Data Modelling

Data Modelling is the backbone of Power BI.

A single error in the data model can have consequences on the entire report.

In Power BI, there are five types of data modelling:

🎯 Conceptual: Creates a high-level view of the data

🎯 Logical: Defines the structure of the data independent of any specific technology

🎯 Physical: Implements the logical data model in a specific technology or system

🎯 Dimensional: Organises data into dimensions and facts to support complex reporting and analysis

🎯 Tabular: Specific to Power BI, it involves creating a data model in the form of tables and relationships for fast and interactive reporting

When you connect multiple tables in Power BI, it's important to know how to handle the data from these different tables. 

The data will only flow between the tables once you establish a relationship between them.

Hence, before you can visualise the data, you need to model it correctly.

Having knowledge of data modelling concepts like cardinality (relationship between tables) can help to avoid errors in your data model.

Another important factor to consider is the direction of data flow when transferring data from one table to another, whether it is flowing in a single direction or bi-directional.

🔷 Data Visualisation

To create an effective report, ask these questions:

• Who is your audience?
• What do they want?
• How will you communicate it?

Simply putting data into a visual without considering its suitability is not the correct approach. 

In most cases if your audience consists of senior management, and are just looking for numbers, avoid using technical jargon.  

Set the expectations before creating a report, and get clarity on what are the things they are looking for.

You can also convey the functions and visuals you’ll be using.

When it comes to creating visuals, follow the design principles and colour palette of the client.

Power BI offers a wide range of visuals to help you showcase your data in a meaningful and compelling way.

Some of the commonly used visuals in Power BI are column charts, bar charts, line charts, area charts, pie charts, donut charts, scatter charts, etc.

Example of a Dashboard created in Power BI

Each visual has its own strengths and weaknesses so you need to choose the one depending on the information you want to convey.

🔷 Data Storytelling

When you're in an interview, you’ll be simply asked to describe a report you created and walk the interviewer through it. 

This narration is called data storytelling. 

You need to create a narrative that takes the interviewer from the introduction of your report all the way to the conclusion.

To do this, it's important to structure your report in a way that tells a cohesive story.

Break down your story into three parts: an introduction, the main body, and a conclusion. 

In the introduction, you should set the stage for the story you're about to tell. 

In the main body, you'll provide the meat of the report - the data, analysis, and insights that support your story.

And in the conclusion, you'll tie everything together and leave the interviewer with a clear takeaway.

By doing this, you can effectively communicate the story behind your data in a clear and interesting manner.

🔷 Sharing Reports

You should be aware of the different ways of sharing a report in Power BI.

You can share it via email, generating a link, a QR code or even via the Power BI mobile app.

Each method has its advantages, so it's up to you to decide which one works best for your needs.

🔷 Cloud Knowledge

Power BI has three main components- Power BI Desktop, Power BI Service and Power BI Mobile.

You use Power BI Desktop to develop your reports, and then you can deploy and share them using Power BI Service.

It's worth noting that Power BI Service is built on the cloud, which means it's accessible online and you can store and access data and applications remotely, which can be convenient and cost-effective.

Hence, having a basic understanding of the cloud can be helpful in working with Power BI Service. 

Why Power Bi?

Power BI is a standalone Microsoft Business Intelligence Product, which includes both desktop and web-based applications for loading, modelling and visualising data.

It helps you to:

⭐️ Connect, transform and analyse millions of rows of data

Access data from virtually anywhere (database tables, flat files, cloud services, folders, etc.), and you can also automate data shaping and loading (ETL) procedures to save tons of time and effort

⭐️ Build relational models to blend data from multiple sources

Create table relationships to analyse holistic performance across an entire data model

⭐️ Define complex calculations using Data Analysis Expressions (DAX) 

Manipulate data and enable advanced analytics with powerful and portable DAX expressions

⭐️ Visualise data with interactive reports & dashboards

Build custom business intelligence tools with best-in-class visualisation and dashboard features

⭐️ Power BI is the industry leader among BI platforms

Microsoft Power BI is intuitive, easy to use, powerful and absolutely FREE to get started

Components of Power Bi 

This complete ETL Tool has three components that work together seamlessly to provide a complete solution for creating, sharing, and accessing data insights.

▶️ Power BI Desktop allows you to create data models, reports, and dashboards. It has a drag-and-drop interface that makes it easy to import data from multiple sources that you can transform.

You can use the available functions to remove duplicates, replace values or even change the data type. Using the DAX functions, most operations can be executed. 

▶️ Power BI Service is a cloud-based service that allows you to publish, share, and collaborate on your reports and dashboards. 

It also offers various sharing and collaboration tools to explore. You can also create security rules to restrict access to certain data based on predefined roles.

▶️ Power BI Mobile is a mobile application that allows you to view and interact with your reports and dashboards on the go available for both iOS and Android devices.

Recommended readings:

Senior Data Analyst Interview Preparation Guide

Accenture Data Analyst Interview Preparation Tips

Power Bi vs Tableau

Power BI has become the industry leader as per the Gartner metric accepted globally.

For the last 3 to 4 years Power BI is in the leader quadrant and it has surpassed Tableau.

Microsoft, the driving force behind Power BI, has achieved this status through its usability and the added advantage of being a free tool

If you compare the pricing of Tableau and Power BI, there is a huge difference. 

If you have the Microsoft 365 licence, you can access Power BI by default.

Tableau has limitations, particularly when it comes to security features, and the charges are also substantially high.

Overall, Power BI is not only a powerful visualisation tool but also offers a comprehensive set of features at a more affordable price compared to its competitors like Tableau.

DAX and its importance

DAX or Data Analysis Expressions is a formula language used in Power BI to analyse and manipulate data. 

It's designed to perform calculations, create new calculated columns and tables, and define measures within your data model.

Creating Effective DAX formulas will help you to get the insights you need and understand your data better.

It consists of more than 300 functions that allow you to manage and transform your data to derive meaningful insights.

However, you don’t have to get familiar with all of them. Focus on the functions that are mostly used in Power BI such as Filter, Calendar, Aggregate, etc.

Along with the syntax, also understand the limitations and uses of the DAX functions in order to clear your interviews.

How to learn Power Bi?

🔶 Enroll in an online course

You can find a lot of courses that provide hands-on experience covering topics such as data visualisation, creating reports, and working with data models in Power BI.

However, stay away from courses that claim you can learn Power BI in 3 hours. These courses will not help you if are trying to learn all the components of Power BI. 

Some popular courses include Microsoft's official Analysing and Visualising Data with Power BI on edX, and Udemy's Microsoft Power BI - A Complete Introduction.

🔶 Learn the basics of Power Apps and Power Automate

Power Apps allows you to build custom applications that can be used within Power BI.

And, Power Automate enables you to create workflows that automate repetitive tasks.

These two tools in Microsoft Power Platform can complement your skills in Power BI  and can help you create custom apps and automate workflows in Power BI.

🔶 Get your hands on the premium feature 

To try out the latest Power BI functionalities, you’ll need the premium licence that you can get by enrolling in the Microsoft Developer Program. 

This program is designed for people who are new to Microsoft tools. Under this program, you’ll get a premium licence for 60 days. 

This will help you to tackle the interview questions that can be asked related to the premium feature.

🔶 Complete Power BI Data Analyst Certification - PL-300

This certification is offered by Microsoft and adding this to your portfolio can demonstrate your expertise and proficiency in Power BI to potential recruiters.

I highly recommend taking this certification.

The exam covers topics such as connecting to data sources, designing and developing data models, creating and formatting visualisations, and managing and sharing reports and dashboards.

🔶 Participate in data challenges

Don’t just limit yourself to courses, practise with real-world data and get your hands dirty.

Search for Power BI data challenges online, they’ll provide you with sample data sets and problem statements.

Create a Power BI report using these sample data and publish it and don’t forget to showcase your work on LinkedIn.

Practising with real-world data can help you develop your skills and understand how Power BI can be used in different industries and scenarios.

🔶 Stay updated with the latest updates in Power BI - check monthly features

As a recruiter, my first question is usually about the latest update or features in Power BI.

Microsoft releases new features and updates for Power BI every month. 

So, stay updated with all the latest trends by checking the monthly features, and experimenting with new functionalities to expand your skills and capabilities.

This shows the interviewer that you are seriously following the updates and using the tool day in and day out.

🔶 Take mock interviews and get feedback

Nothing can beat preparing with an experienced professional when it comes to skills or interviews.

To identify areas of improvement and refine your skills, feedback is crucial.

You can connect with me on a 1:1 session so that I can help you strengthen your Power BI skills and crack your Data Analyst interviews.

🔶 Create an Effective Power BI Resume

Focus on Numbers. 

Talking in terms of numbers will always be effective as these show the impact that you have created.

Some examples of numbers that you can showcase on your Power BI resume are:

• Number of reports and dashboards created
• Data sources connected
• Mention the key performance indicators (KPIs) that you were able to improve
• The amount of time you were able to save through Power BI automation 
• The amount/percentage of revenue that was generated as a result of your analysis

Wrapping it up

Learning Power BI is a surefire way to crack your data analyst interviews.

With so many capabilities, it is the perfect tool for anyone looking to excel in the world of Data Analysis.

Let me also address that learning anything new can be intimidating. So take one step at a time.

There are lots of resources at your disposal, both free and paid. And once again, don’t be afraid to ask for help.

You can always reach out to me for a FREE 1:1 strategy session where we can discuss your pain points and clear your doubts.

With the right attitude and a little bit of hard work, you'll be a Power BI pro in no time!

Also read: Overcoming Rejection: Divya’s Journey to a Data Analyst Role