DAX (Data Analysis Expressions) is a functional formula language developed by Microsoft for data modeling and analytical calculations in Power BI, Excel Power Pivot, and SQL Server Analysis Services. Unlike traditional spreadsheet formulas, DAX operates on tables and columns rather than cell references, enabling dynamic aggregations that automatically respond to filter context. The key to DAX mastery lies in understanding evaluation contexts: filter context (what's being filtered), row context (iterating through rows), and context transition (how CALCULATE bridges the two) — once you grasp these three concepts, even complex DAX patterns become intuitive.
What This Cheat Sheet Covers
This topic spans 27 focused tables and 193 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
Table 1: Core Calculation Types
| Type | Example | Description |
|---|---|---|
Total Sales = SUM(Sales[Amount]) | • Dynamic calculation evaluated in filter context • recalculates based on slicers, filters, and visual selections • does not add to model size. | |
Profit = Sales[Revenue] - Sales[Cost] | • Static row-level calculation evaluated in row context • computed once during refresh • stored in model • increases file size. |