Hi @aherz,
You are right about not being able to iterate through values within MDX.
This is the limitation of this language and is going to stay the same. If you need to iterate through the string to retrieve and sum up values - you need to do it during the data import.
Iteration through the field values once for each issue during the data import is more efficient than iteration during each report execution.
The measure should return the data in the same format in all conditional branches.
If you only want to display the value or error message, you might consider displaying a text string created from the measure value via the CAST() operator or error message in the case of an error. The numbers would not look very nice as they will be aligned to the left. Moreover, you might not be able to further re-use that measure in any other calculations without re-converting it back to the numeric value. This option is far from perfect, but might work in desperate need.
You might use the Cache() function to wrap reusable code. The next time, when the same code is executed - the eazyBI will check if the value exists and then re-use it instead of re-launching the same code.
Please read more about that here - Cache.
Regards,
Oskars / support@eazyBI.com