← Back to Chapters

DAX Fundamentals

? DAX Fundamentals – From Zero to KPI Report

? Quick Overview

DAX (Data Analysis Expressions) is the calculation language of Power BI. It is used to create calculations, KPIs, and business logic. This lesson assumes the student knows nothing about DAX.

? Key Concepts

  • DAX works on tables and columns
  • Measures are evaluated at query time
  • Filter context controls results
  • CALCULATE modifies context

? Syntax / Theory

A basic DAX measure follows a simple pattern:

? DAX Measure Syntax 
// Generic DAX measure syntax
Measure Name = FUNCTION(Table[Column])

? Sample Data Used for DAX Practice

? Sales Data 
// Clean sales data
OrderID,Product,Quantity,Sales,Cost
1,Laptop,2,2000,1500
2,Mobile,1,1500,1100
3,Laptop,3,3000,2200
4,Keyboard,1,800,500
5,Mouse,2,600,300
6,Mobile,2,3000,2100

? Code Examples

? Total Sales Measure 
// Calculate total sales
Total Sales = SUM(Sales[Sales])

? Live Output / Explanation

Result Explanation

The Total Sales measure dynamically recalculates based on filters such as Product, Date, or Region applied in the report.

? Interactive Example (Conceptual Flow)

? Filter Context Flow 
// Visual filter interaction example
User selects Product = Laptop
Power BI applies filter context
DAX recalculates measure
Visual updates automatically

? Use Cases

  • Building KPI dashboards
  • Creating dynamic business logic
  • Replacing Excel formulas
  • Advanced reporting and analytics

⚡ DAX Live Simulator

Change the filter or function to see how the DAX formula and result change instantly.



// Active DAX Formula: Total Sales = SUM(Sales[Sales])
Total Sales (All)
$10,900

? Tips & Best Practices

  • Prefer Measures over Calculated Columns
  • Keep measures simple and reusable
  • Understand filter vs row context
  • Name measures clearly

? Try It Yourself

  1. Create an Average Sales measure
  2. Build a High vs Low profit flag
  3. Create a product-wise sales table