Drill through from cube report to relational report

[Deep750]

Hi,
I have a source report, that has Dynamic Cube as source, and a target report, that is relational. DB is Oracle.

I'm having a issue with drill through. I am trying to send a chosen parameter for time to a relational report.
The value prompt consists of regular time members and relative time members.
The case is that the businessKey for the parameter that is sent, when drilling, for the regular members , is e.g. '2015', while the relative time members businessKey that is sent is NULL.
I tried to create a CASE-statement in the target report, I have to take in to account different scenarios, but to keep it simple:

Code Select Expand

[PERIOD] = CASE WHEN ?PARAMETER? BETWEEN 2000 and 3000 THEN ?PARAMETER? ELSE EXCTRACT(YEAR; SYSDATE()) END to take hand of the relative time member, but no luck, as I'm getting an error that parameter has different data types.

Does anyone have any suggestion on how to solve this?