I need to perform a calculation where I substract the value of my current member from the value of the previous member. However sometimes the previous member is empty, in which case, I want to use the first non empty previous member available.

This is a slimmed down copy of my query. I've been playing around with various functions like parallelperiod, prevmember, isempty etc... but haven't managed to work it out yet. Any help appreciated!


MEMBER [measures].[subscriptions previousMember] as

MEMBER [measures].[subscriptions change] as
'[measures].[subscriptions] - [measures].[subscriptions previousMember]'

SELECT non empty {[Time].[Time].[2008].[Q3].[sep]:[Time].[Time].[2013].[Q4].[dec]} on columns,
[measures].[subscriptions previousMember],
[measures].[subscriptions change]} on rows
FROM [subscription facts]