The Data Analysis Expressions language allows you to perform custom calculations and organize information to manage visualizations with Excel and Power BI.

It is not a programming language but a formula language. It is mainly used for calculated and measured columns. In addition to formulas, DAX includes some additional functions designed to work with relational data and perform dynamic aggregation and functions that are used in formulas.

It is a very useful plugin to make impressive interactive visualizations with Power BI

DAX Programming

Using DAX  

• Syntax 
• DAX Traders Reference 

• DAX Parameter Naming Conventions 
• DAX Function Reference 
• DAX formula support in DirectQuery mode 
• DAX queries 
• DAX error references 

• Most common DAX use cases