DAX function

TREATAS — DAX function reference

Apply one table as a filter on another.

Syntax

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TREATAS(<table>, <columnName1> [, <columnName2>, …])

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CALCULATE([Sales], TREATAS(VALUES(Budget[Region]), Sales[Region]))

→ A number

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CALCULATE(SUM(Sales[Amount]), TREATAS(VALUES('Date Selector'[SelectedYear]), 'Date'[Year]))

→ Applies a disconnected slicer table's selection as a filter on the real Date table

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CALCULATE(SUM(Sales[Amount]), TREATAS(FILTER(ALL(Product), Product[Margin] > 0.4), Product[ProductID]))

→ Filters Sales by a computed set of high-margin products with no direct relationship needed

A virtual relationship — filters across tables that are not physically related.
TREATAS matches by column position, not by name — the Nth column of the source table is applied as a filter on the Nth target column listed, so column order matters even if the names differ.
It creates a genuine virtual relationship for that one calculation (unlike LOOKUPVALUE, which just looks up a value) — the standard technique for parameter tables and what-if scenarios where a physical relationship would be inappropriate or create ambiguity.

From Relationships