I stumbled across the following challenge in FME:
how to deal with NULL values if you want to perform a calculation for a new attribute. For example, I want to sum up values (could be any other kind of arithmetics).
The expected result is fine as long as no NULL Value is involved. FME turns any calculation into a NULL result if any NULL is involved (see documentation).
The question that haunts me is, how to treat those NULL values as 0 in the calculation without changing the value to an actual 0 (as the NullAttributeMapper would). The result I am looking for is the following: If all values are NULL i want the result to be NULL, otherwise I want the NULL value to be treated as 0. Furthermore, I dont want the NULL values to be changed to 0, so I can distinguish between NULL and 0 in further calculations.
