What is DAX (Data Analysis Expressions)?
DAX is the formula language used in Power BI and related Microsoft tools to create calculations such as totals, ratios and year-over-year comparisons. It works on data models rather than individual cells.
Why it matters for your business
Well-written DAX makes Power BI reports accurate and fast, and keeps business definitions like gross margin consistent across every report.
One DAX measure calculates revenue for the same period last year, and every chart in the sales report uses it.