With DAX queries, you can query and return data defined by a table expression. Data Analysis Expressions (DAX) Reference. What is a Query Language? A query language is a programming language that allows you to send a request to a database and then receive data. Data Analysis Expressions (DAX) is the native formula and query language for Microsoft PowerPivot, Power BI Desktop and SQL Server Analysis Services. DAX means Data Analysis Expressions and it is a simpler query language than MDX. Write (SQL) queries to process data and calculate the business metrics; Design code to create charts with interactive widgets to visualize the.