variables dax
The VAR keyword introduces variables in an expression. The syntax after VAR defines a variable, which can be consumed in following VAR statements or within the mandatory RETURN statement following the declaration of one or more variables. There are many benefits of using the VAR syntax, particularly when you also use in line comments. The formulas can be easier to write. It may seem to take more time to write the formula at first, but you may just end up saving that time by getting to a working version of the formula faster, with less rework. The formulas can be easier to read. A reader can understand the logic of the formula step by step and hence it can be easier to work out what the formula is designed to do. This is particularly true when the author uses comments, new lines and spacing as well. The formulas can be easier to maintain when changes are needed. Formulas that use repetitive sub strings of DAX can be written once and then used many times. This is good for formula writing but also for performance (although DAX already had some good caching features prior to this syntax) . Given the variables are executed in the initial filter context, this syntax can be an easier alternative to using the EARLIER function (when you have nested row contexts inside a complex formula).