Returns the value in the column for the very first point at which there was a row context.
The column that contains the desired value.
The current value of row, from ColumnName, at the outermost row context.
EARLIEST retrieves the value from the outermost row context.
It is recommended using variable (VAR) saving the value when it is still accessible, before a new row context hides the required row context to access the desired value.
Learn more about EARLIEST in the following articles:
Variables in DAX
In this article, you learn a new feature in DAX 2015: variables. The 2015 version of the DAX language has many new functions, but none of them is a game changer for the language as variables are. » Read more
DAX coding style using variables
This article shows how variables in DAX can impact the coding style, simplifying a step-by-step approach and improving the readability of your code. » Read more
Other related functions are:
Contributors: Alberto Ferrari, Marco Russo
MSDN documentation: https://msdn.microsoft.com/en-us/query-bi/dax/earliest-function-dax