Power BI DAX – DAX is a grouping of functions, operators, and constants that can be used in a formula and expression or simply to calculate and return one or more values. To summarise PBI DAX helps you create new insights from data already in your model.
The DAX toolset is also embedded in other Microsoft products such as Power Pivot and SSAS Tabular.
DAX can be classed as a functional language, which in practice means the executed code set can be contained inside a function.
What is Power BI DAX?
In simple words, DAX is used for data manipulation – to create new data and insights
There are two main calculations you can create using PBI DAX:
- calculated columns
- calculated measures
Important DAX Functions in Power BI
- LOOKUP( )
- FILTER( ) & CALCULATE( )
- Nested IF Condition
- Splitting a String Based on Delimiters
- Fetching a Particular Letter from a Word
- Conditional Formatting
- The ALL Function
- RELATED(<column>) – This DAX function is designed to help you return a related value from another table in addition to the one you are working on
Useful DAX Functions
The most useful PBI DAX function is probably the CALCULATE function given this is one of the most important and multipurpose functions in DAX Power BI.
The DAX calculate function can simplify complex, multiple calculations easily.
The DAX CALCULATE function assesses an expression in a context that is changed by specific filters. Below is a basic example of the relevant DAX expressions:
CALCULATE(<expression>, <filter1>,<filter2>