DAX Function to Calculate Sum of Turnover from Previous Month

This section outlines a DAX function that computes the turnover from the previous month without using the VAR keyword.

Function Overview

The function, PreviousMonthTurnover, will:

• Aggregate the turnover measure from the previous month.
• Handle date filtering directly within the measure.

Code Implementation

Here’s the DAX code for the measure:

PreviousMonthTurnover = 
CALCULATE(
    SUM(Sales[Turnover]),  // Sum of the Turnover column
    PREVIOUSMONTH(Sales[Date])  // Filters to the previous month using the Date column
)

Explanation of Code Components

1. CALCULATE: The main function for modifying the filter context to compute the sum of turnover.
2. SUM(Sales[Turnover]): Specifies the column from which we are summing values (Turnover).
3. PREVIOUSMONTH(Sales[Date]): This function shifts the date context to the previous month based on the Date column in the Sales table.

Input Validation

• This code assumes the Sales table contains a Turnover numeric column and a Date column with valid date values.
• Ensure that the Sales table is not empty to prevent errors.

Example Usage

Scenario

Assuming you are working on a sales dashboard, you want to display the turnover from the previous month alongside the current month’s turnover.

Application in Report

You can add this measure to your Power BI report:

• Create a card visual to show the previous month's turnover.
• Include additional visuals that contrast it with the current month turnover for insights.

Conclusion

This succinct DAX measure allows for efficient computation of turnover from the previous month without using the VAR keyword. For deeper understanding and further examples, consider exploring resources on the Enterprise DNA Platform to enhance your DAX skills. This approach not only simplifies your calculations but also demonstrates best practices in DAX coding.