Power BI - How to create custom column?

In Power BI, irrespective of the data source we are importing data from, we are provided multiple options to modify it. One of the options available in Power BI is to create a custom column, i.e., using the columns present in our data by default, we can create custom columns and use that in our visualizations. To understand how custom columns are made, we will use the sample financial dataset provided by Power BI. 

On launching the Power BI Desktop App, we get an option to Try the sample dataset; by clicking on that option, we can import the sample Financial dataset and start using it to create our Power BI Report. 

Dataset Description

The dataset gives insights into the Sales and Profits of certain products belonging to different segments in multiple countries over 2013-14. It comprises the following columns by default:

Creating Custom Columns in Power BI using Arithmetic Operations

Suppose we want to plot a line chart of profit percentage vs. segment and analyze which part has the highest profit percentage and which has the lowest; so to do this, we will have to create two new columns, which are:

TotalManfacturingPrice - [Manufacturing Price]* [Units Sold]
ProfitPercentage - ([Profit]/[TotalManufacturingPrice])*100

Creating Line Chart in Power BI

Step 1: First, navigate to the Data Tab and select the Table Tools options from the top navigation bar. Select the New Column option from the table tools and opportunities to create a new custom column.

Step 2: On clicking the New Column option, an input bar will appear where we will write a simple DAX expression to create our columns.

Step 3: Data Analysis Expressions (DAX) is the native formula and query language for Microsoft PowerPivot, Power BI Desktop, and SQL Server Analysis Services Tabular models. In DAX, we can access a particular column using the following syntax - tableName[columnName], The following DAX Expression creates a new column named TotalManufacturingPrice.

     TotalManufacturingPrice = financials[Manufacturing Price]*financials[Units Sold]

Step 4: Now, using this newly created column, we make our ProfitPercentage column using the below expression.

ProfitPercentage = (financials[Profit]/financials[TotalManufacturingPrice])*100 

Step 5: Now, Select the Line chart from the Visualization. Drag the segment and drop to the X-axis , Again drag the ProfitPercent and drop to the Y-axis that we have created our custom columns, we can use line chart which comes out to be like this:

Creating Donut Chart in Power BI

Next, we will create another custom column called ProfitType to tell if the profit is positive, negative, or null. This can be done by using the IF function in the DAX Expression like this:

ProfitType = IF(financials[Profit]<0,"Negative",IF(financials[Profit]>0,"Positive","NULL")) 

Step 1: From the top navigation bar, select the New Column option from the table tools and opportunities to create a new custom column.

Step 2: Select donut chart from the Visualization. From the field option drag the ProfitType and drop to the values and details. This newly created column can be further used to create a donut chart, as shown below:

Creating a Bar Chart in Power BI

Suppose we also want to analyze which day of the week has the most significant number of sales or profit; so for this, we can create an additional column, Weekday, by extracting the day of the week from the Date Column already provided using the DAX WEEKDAY function like this:

Weekday = WEEKDAY(financials[Date].[Date],2)

Here, the second parameter of the function refers to the return type. 

• If return type = 1, week begins on Sunday (1) and ends on Saturday (7). numbered 1 through 7.
• If Return type = 2, week begins on Monday (1) and ends on Sunday (7).
• If Return type = 3, week begins on Monday (0) and ends on Sunday (6).numbered 1 through 7.

For the above function return type is 2, i.e the week begins on Monday.

Step 1: On clicking the New Column option, an input bar will appear where we will write a simple DAX expression to create our columns.

Step 2: Using this custom column, we can plot the following bar chart and conclude that we get Maximum Profits on Tuesdays ( Weekday = 2)