How to get a formula column by row sub group

[#1]

Hi ms,

Thanks for the update. The local approach delivers the results, without error code from the formula editor.

By the way, what is the difference between Parameter() and local()?

[#2]

As I understand it, Local() simply let variables to be defined and evaluated within the context of the column formula, eliminating risk of interference with global variables with the same name. Parameters are used in optimization problems, i.e. the nonlinear platform.

[#3]

Thanks