Guided Notes
Introduction to DAX
Measures, and how DAX differs from a spreadsheet formula.
DAX (Data Analysis Expressions) is the formula language used in Power BI, Power Pivot, and Analysis Services to define calculations called measures — e.g. `Total Sales = SUM(Sales[Amount])`.
Unlike an Excel formula tied to one cell, a DAX measure recalculates dynamically based on filter context — the same measure returns a different number depending on which slicers, filters, or report visuals are applied.
The most important DAX skill isn't memorizing functions, it's understanding filter context: what rows are 'currently visible' to the calculation at any given moment.