# Power BI Blog: “X” and “Non-X” functions in DAX

30 September 2021

*Welcome back to this week’s edition of the Power BI blog series. This week, we discuss the difference between “X” and “Non-X” functions in DAX.*

**DAX** in both PowerPivot and Power BI includes numerous aggregation and statistical functions that are similar to formulas in Excel. Some of them end with an “**X**”. For example:

You may wonder how and when we can apply each of them. It’s simple:

**“Non-X” functions:**only use a single column as a parameter. The syntax is as follows:

**=***FunctionName***(column)**

**“X” functions:**specify a table, evaluate expressions for each row of that table (*i.e*. each record) and generate a result based on the set of values. The syntax is as follows:

**=***FunctionName***(table, expression)**

Therefore, if you already have a column with a set of values to calculate the result on, you can use “non-**X**” functions. For example:

**Total Sales = SUM(Sales[Amount])**

On the other hand, you should use “**X**” functions when you need to create a new set of values based on existing data. For instance:

**Total Profit = SUMX(****Sales, ****Sales[Revenue] - Sales[Cost])**

You may also use them to apply some conditions before calculating. For example:

**Total Profit of Product 1 = SUMX(****FILTER(Sales, ****Sales[ProductID] = 1), ****Sales[Revenue] - Sales[Cost])**

In this example, the **SUMX** function will store the calculated values of each row on a virtual column and then take the **SUM** of all rows in that column.

*Check back next week for more Power BI tips and tricks!*