Strategy has two kinds of transformations, expression-based transformations and Table-based transformations. As to the Month-to-Date(MTD) calculation, creating a table-based transformation, and a transformation metric is a general way. This article explains how to use a function Runningsum to achieve this instead.
Runningsum function returns the running sum of the values in a list, adding the current value to the preceding values. It can be used to maintain running totals of values in specific categories as well as an entire set. The calculation can restart based on attributes identified in the parameter settings. This is an OLAP function.
For more information about function Runningsum, please check the product manual < Strategy Functions Reference>
