Understanding SUMX Function in DAX

Explanation of SUMX Function in DAX

1. Code Overview

The SUMX function in DAX (Data Analysis Expressions) is used to iterate over rows in a table, calculate an expression for each row, and then sum the results.

2. Syntax

The general syntax of the SUMX function is:

SUMX(table, expression)

3. Parameters

• table: The table or an expression that returns a table over which the iteration will happen.
• expression: The expression to be evaluated for each row of the table.

4. Working Principle

• For each row in the specified table, the expression provided is evaluated.
• The results of the expression for each row are summed up to produce a single scalar value.

5. Use Cases

• Commonly used in scenarios where calculations need to be performed row by row, such as calculating cumulative values, weighted averages, or performing complex calculations based on row-level data.

6. Example

Consider a DAX code snippet using SUMX:

TotalSales := SUMX(Sales, Sales[Quantity] * Sales[Unit Price])

In this example:

• The Sales table is iterated row by row.
• For each row, the product of Quantity and Unit Price is calculated.
• The results of these calculations are summed up to get the total sales.

7. Key Point

• SUMX is a versatile function in DAX that allows for flexible row-by-row calculations on tables.
• Understanding how to properly structure the table argument and expression is crucial for accurate results.

By mastering SUMX and other DAX functions, you can perform complex calculations and analysis in Power BI or Excel. For more in-depth learning, consider courses on the Enterprise DNA Platform.