What is Power BI?
Introduction
Throughout this month, I've posted many projects that involved wrangling data through SQL. However, I am going to shift gears and start playing around with a data visualization tool called Power BI.
Power BI is a great way to gain insights from your data as it is much easier to understand large amounts of numbers by looking at visuals rather than looking at rows and columns of data.
I've chosen to use Power BI because I love the GUI of the app, and it is very easy to learn; there are many free tutorials online that could get you started.
In this post, I'm going to walk through the main features of the Power BI Desktop app, so if you're interested in learning about the basics of this powerful data visualization tool, keep reading!
Workflow within Power BI Desktop
Power BI Desktop is the app that is free for anyone. You can do many things with the free version such as cleaning data, creating visuals, and managing relationships between tables. However, the downside is that you cannot collaborate together with others and share your work to the public. To do that you must use a paid version called Power BI Pro.
I'm only going to be focusing on Power BI Desktop since anyone has access to it.
There are 3 main steps when working inside Power BI Desktop:
- Query Editor (Connect the data, cleaning data phase)
- Data Model (manage relationships)
- Report (make visuals)
I will explain the function of each step and how it looks like in the app.
Query Editor
This is the first step in the workflow. You can't create any visuals if you do not have any connected data! Therefore, you must know how to import your data.
Once you open the Power BI Desktop, go to the "Home" button and click on "Get Data". It looks like this:
There, you can import your data from various sources such as Excel, SQL Server, Microsoft Access, and many more. It's cool how Power BI can connect to data from so many different servers.
After you click on the dataset that you want, you will see a pop-up appear on your screen. On the bottom of the pop-up, you will see three options "Load", "Transform Data", and "Cancel".
Even though the "Load" button may look more appealing, don't click it! You should click on "Transform Data" first because you want to be able to clean your data before you load it onto Power BI.
Once you click on "Transform Data", a new window will appear. This window is called the "Query Editor". It looks something like this:
Here, you can clean data by removing null values, changing the format of the columns, etc.
After you're done with cleaning, you can click the "Close & Apply" button on the top left corner of the Query Editor and you're ready to move on to the next step!
Data Model
After you have imported and cleaned the data in the Query Editor, you can now head over to the Data Model. It looks like this:
If you have more than one table in your database, it is important to create relationships between them in order to display the correct information in your visuals.
The Data Model is cool because it shows you a nice diagram of all the tables and the relationships between them. Here's an example:
You can also use DAX formulas to create new measures and new columns. You can do this by clicking on the "Home" ribbon like so:
DAX stands for Data Analysis Expressions and can help you gain new information from the already existing data that can help you make your visuals in the next step. DAX is probably one of the most important things that you should learn because there are a wide variety of powerful functions such as SUMX(), AVERAGE(), COUNTROWS(), and many more.
Report
This is my favorite part of the process. If you love art, now is your time to shine. You can create stunning visuals that answer any statistical questions that you have.
To go to the "Report" tab, go to the left hand side and click on the little icon at the very top:
What I love about this stage in the workflow is that you can be as creative as you want in your visuals.
Here's an example of a report that I made in my free time:
The colors and charts/graphs make it very easy for others to gain insights from the data just from a quick glance at the report.
Conclusion
I hope you liked my overview of Power BI! In my next post, I will create a full visual report on the Pizza Sales SQL project that I did in a previous post over here, so stay tuned for that!
Anyways, I hope you have a good day and thank you for reading!