Creating table functions in DAX using DETAILROWS
A Tabular model in compatibility level 1400 provides a property named Detail Rows Expression, which is designed to provide control over drillthrough results from MDX queries. The same table expression can also be evaluated in DAX by using the DETAILROWS function. As of July 2018, this is the only way to define a table expression in a Tabular model that can be reused in other DAX expressions. Therefore a possible alternative use of this feature is defining a complex table expression in a single place – then reusing it in multiple places by just invoking a DETAILROWS function. Special thanks to Daniel Otykier for sharing the original idea.