Module 4
5 min read
Introduction to DAX
Learn the basics of DAX formulas in Power BI
What is DAX?
DAX (Data Analysis Expressions) is Power BI's formula language.
Like Excel formulas, but works on entire columns and tables.
Calculated Columns vs Measures
| Type | When Calculated | Use For |
|---|---|---|
| Calculated Column | During refresh | Row-level values, filtering |
| Measure | Real-time | Totals, averages, dynamic calcs |
Use measures whenever possible - they're faster and flexible.
Basic Syntax
Column:
FullName = [FirstName] & " " & [LastName]
Measure:
Total Sales = SUM(Sales[Amount])
Create a Measure
- Click table in Fields pane
- Table Tools > New Measure
- Type:
Total Sales = SUM(Sales[Amount]) - Press Enter
Essential Functions
| Function | Example |
|---|---|
| SUM | SUM(Sales[Amount]) |
| AVERAGE | AVERAGE(Sales[Amount]) |
| COUNT | COUNT(Sales[OrderID]) |
| IF | IF([Amount] >= 1000, "High", "Low") |
| DIVIDE | DIVIDE([Profit], [Revenue]) |
Quick Tips
- Always use Table[Column] format
- Use DIVIDE() instead of / operator
- Use measures for aggregations, not columns
Master SUM, AVERAGE, COUNT, and IF first. Everything else builds on these.