Syntax
Table of contents:
- Explain the functions
- Calculate the sum of distinct values
- Calculate the sum of subcategories (or categories)
- Sum child values into the parent
1. Explain the functions
In the video below, we will go through: how to use SUM() and SUMX(), the difference between them and when should we use one vs the other.
The DAX SUM function calculates the sum of all numbers in a column while the DAX SUMX function returns the sum of an expression for each row in a table.
02:28 Create a measure to calculate the total sales using SUMX function
03:40 Create a calculated column for total sales (row by row)
05:16 Create a measure to calculate the total sales using SUM function
06:00 Difference between SUM and SUMX

Remarks
The SUMX function takes as its first argument a table, or an expression that returns a table. The second argument is a column that contains the numbers you want to sum, or an expression that evaluates to a column.
Only the numbers in the column are counted. Blanks, logical values, and text are ignored.
Example 2: Calculate the sum of distinct values in DAX
Have you ever tried to calculate the sum of distinct or unique values in Power BI? Not straight forward right?
A distinct sum is a sum where you specify the values that you want to have included in the totals. W
In this video tutorial we will go through the wrong and the right way(s) to do it.
Keynotes:
03:37 SUMX Calculation
06:00 Distinct sum with MAX as part of the expression
08:00 Distinct sum with MAX as a measure

Download example file:
To get the files:
1. Go to Curbal Download Center > Dax Fridays
2. Get File #12
Example 3: Calculate the sum of subcategories
Let me show you how to calculate the sum of subcategories.
To get the files:
1. Go to Curbal Download Center > Dax Fridays
2. Get File #57

Example 4: Sum child values into the parent
In today’s video, I will show you how to sum child values into the parent when you are dealing with hierarchies in Power BI.
To get the files:
1. Go to Curbal Download Center > Dax Fridays
2. Get File #91

Hi. The link for the download file is not working anymore. I would really appreciate if you guys check it out. Thank you.
Hi Leandro, thanks!
I just uploaded a working link: http://gofile.me/2kEOD/k9nLfdLZO
/Ruth