Power BI 101, What Should I Learn?

This is the second part of my new series of Power BI posts named Power BI 101. In the previous post, I briefly discussed what Power BI is. In this post, I look into one of the most confusing parts for those who want to start learning Power BI. Many people jump straight online and look for Power BI training courses which there are plenty out there. But which one is the right training course for you? Let’s find out.

What do you want to gain from learning Power BI?

Regardless of attending paid training courses or being a self-learner, the above question is one of the most important questions you might ask yourself before going to the next steps. The answer to this question dictates the sort of training you must look for. Your answer to the preceding question can be one or none of the following:

  • I am a graduate/student looking at the job market
  • I am a business analyst and I want to know how Power BI can help you with my daily job
  • I am a database developer and I want to learn more about business intelligence and data and analytics space
  • I am a non-Microsoft Business Intelligence developer and I want to start learning more about Microsoft offerings
  • I am a system admin and I have to manage our Power BI tenant
  • I am a data scientist and I want to know how I can use Power BI
  • I am just ciourious to see what Power BI can do for me

As mentioned, your answer might not be any of the above, but, thinking about your reason(s) for learning Power BI can help you to find the best way to learn and use Power BI more efficiently. You can spend time and money taking some online courses and get even more confused. You don’t want that do you?

So, whatever reason(s) you have in mind to learn Power BI, most probably you fall into one of the following user categories:

Think about your goal(s) and what you want to achieve by learning Power BI then try to identify your user category. For instance, if you are a student thinking of joining an IT company as a data and analytics developer, then your user category is most probably a Power BI Developer or a Contributor.

To help you find out your user category let’s see what the above user categories mean.

Power BI Developers

The Power BI Developers are the beating hearts of any Power BI development project. Regardless of the project you will be involved with, you definitely require to have a certain level of knowledge of the following:

  • Data preparation/ETL processes
  • Data warehousing
  • Data modelling/Star schema
  • Data visualisation

To be a successful Power BI developer you must learn the following languages in Power BI:

  • Power Query
  • DAX

Depending on the types of projects you will be involved in, you may require to learn the following languages as well:

  • Microsoft Visual Basic (for Paginated Reports)
  • Python
  • R
  • T-SQL
  • PL/SQL

As a Power BI developer, you will write a lot of Power Query and DAX expressions. Most probably you require to learn T-SQL as well. The following resources can be pretty helpful:

Continue reading “Power BI 101, What Should I Learn?”

Combining X Number of Rows in Power Query for Power BI, Excel and Power Query Online

Combining X Number of Rows in Power Query for Power BI, Excel and Power Query Online

A while back, I was working on a project involving getting data from Excel files. The Excel files contain the data in sheets and tables. Getting the data from the tables is easy. However, the data in the sheets have some commentaries on top of the sheet, then the column names and then the data itself. Something like below:

Sample data
Sample data

This approach is pretty consistent across many Excel files. The customer wants to have the commentary in the column names when the data is imported into Power BI. So the final result must look like this:

Sample Data to be loaded into Power BI
Sample Data to be loaded into Power BI

The business requirement though is to combine the first 3 rows of data and promote it as the column name.

The Challenge

Let’s connect the Excel file and look at the data in Power BI Desktop.

Connecting to sample data from Power BI Desktop
Connecting to sample data from Power BI Desktop

As you can see in the preceding image, Power BI, or more precisely, Power Query, sees the data in Table format. After we click the Transform Data button, this is what we get in Power Query Editor:

Connected to sample data from Power Query in Power BI Desktop
Connected to sample data from Power Query in Power BI Desktop

We all know that tables consist of Columns and Rows. The conjunction of a column and a row is a Cell. What we require to do is to concatenate the values of cells from the first three rows. We also have to use a Space character to separate the values of each cell from the others.

Column, rows and cells in a Table in Power BI
Column, rows and cells in a Table

In Power Query, we can get each row of data in as a Record with the following syntax:

Table{RecordIndex}

In the above syntax, the Table can be the results of the previous transformation step, and the RecordIndex starts from 0. So to get the first row of the table in the preceding image, we use the following syntax:

#"Changed Type"{0}

Where the #"Changed Type" is the previous step. Here are the results of running the preceding expression:

Getting the first row of a Table
Getting the first row of a Table

So we can get the second and third rows with similar expressions. The following image shows the entire codes in the Advanced Editor:

Power Query expressions in Advanced Editor in Power BI Desktop
Power Query expressions in Advanced Editor

But how do we concatenate the values of the rows?

Continue reading “Combining X Number of Rows in Power Query for Power BI, Excel and Power Query Online”

Quick Tips: Adding Leading Zero to Integer Values (Padding) with DAX and Power Query

Quick Tips: Adding Leading Zero to Integer Values (Padding) with DAX and Power Query

There are some cases that we want to add a leading zero to a digit, such as showing 01 instead of 1, 02 instead of 2 and so on. We have two options to do this in Power BI, doing it in Power Query or doing it with DAX.

Adding a Leading Zero in Power Query

The first method is doing it in Power Query using the Text.PadStart() function.

Here is how the syntax of the function:

Text.PadStart(text as nullable text, count as number, optional character as nullable text)

And here is how the function works:

Text.PadStart(input string, the length of the string, an optional character to be added to the beginning of the string util we reach to the string length)

For example, Text.PadStart("12345", 10 , "a") returns aaaaa12345 and Text.PadStart("1", 2 , "0") returns 01.

Let’s create a list of integer values between 1 to 20 with the following expression:

{1..20}
Creating a List of Integer Values Between 1 to 20 In Power Query
Creating a List of Integer Values Between 1 to 20 In Power Query

Now we convert the list to a table by clicking the To Table button from the Transform tab:

Converting a List to a Table in Power Query
Converting a List to a Table in Power Query

Now we add a new column by clicking the Custom Column from the Add Column tab from the ribbon bar:

Adding a New Column to a Table in Power Query
Adding a New Custom Column to a Table in Power Query

Now we use the following expression in the Custom Column window to pad the numbers with a leading zero:

Continue reading “Quick Tips: Adding Leading Zero to Integer Values (Padding) with DAX and Power Query”

The Story of my Book, “Expert Data Modeling with Power BI”

Expert Data Modeling with Power BI
Expert Data Modeling with Power BI

In 2020, the world celebrated the new year with many uncertainties. Well, life is full of uncertainties, but, this one was very different. The world was facing a new pandemic that never experienced before. The first COVID19 case in New Zealand was confirmed in February 2020. In March 2020 the entire country went to lockdown for the first time. The world was experiencing a massive threat changing everyone’s lives. I was no different. Every day was starting with bad news. A relative passed away; a friend got the virus; the customers put the projects on hold etc. Nothing was looking normal anymore. You can’t even go to get a proper haircut, because everyone is in lockdown. This is me trying to smile after getting a homemade haircut. I bet many of you have done the same thing.

Soheil's Homemade Haircut
Soheil’s Homemade Haircut

One day, I checked my email and saw a message from Packt Publishing. They wanted to see if I am interested in writing a book about Power BI. That was a piece of good news after a long time. I always wanted to write a book about Power BI. Indeed, I attempted for the first time in 2016, but I couldn’t manage to get my ducks in a row to grasp the publishers’ attention.

I was not unfamiliar with writing books; indeed, I wrote my first book back in 2006 about Multimedia Applications in Persian. One of my passions in life is listening to music. And CDs were the most accessible music source with high-quality sound. I recall I saved money for some months, and I bought a Discman to listen to the music on the go. But CDs are rather bulky, and you could not have many of them in your pocket. So the next project was to save even more money to buy an MP3 player. But, converting Audio CDs to MP3 without compromising a lot on the sound quality was a real challenge for many people. And, that was my motive to write my first book in Persian to share my little knowledge with everyone. 

Continue reading “The Story of my Book, “Expert Data Modeling with Power BI””