Calling this function returns the median of a set of values calculated by taking the absolute value of the difference between the median of all values in a group and each value. When dragging a Median Absolute Deviation element into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Aggregation > Time Series > Median Absolute Deviation
A Column or other non-aggregate expression can be moved over the (empty-Value Expression) branch of the tree.