DAX (Data Analysis Expressions) is a formula expression language and can be used in different BI and visualization tools. DAX is also known as function language, where the full code is kept inside a function. DAX programming formula contains two data types: Numeric and Other. Numeric includes - integers, currency and decimals, while Other includes: string and binary object.
The DAX language was created specifically for the handling of data models, through the use of formulas and expressions. DAX is used in several Microsoft Products such as Microsoft Power BI, Microsoft Analysis Services and Microsoft Power Pivot for Excel. These products all share the same internal engine, called Tabular.
This article is for users new to Power BI Desktop. It gives you a quick and easy introduction on how you can use Data Analysis Expressions (DAX) to solve a number of basic calculation and data analysis problems.
https://learn.microsoft.com/en-us/power-bi/transform-model/desktop-quickstart-learn-dax-basics
In this step-by-step tutorial for beginners, learn how to use DAX (Data Analysis Expressions) in Microsoft Power BI. DAX is a formula language with functions. If you've ever written formulas in Excel, you'll find that DAX is very familiar.