Date Logics

Hi,

I had an requirement to display date as an report header like 9+3 (forecast and actuals) examples.

Date is an webi input prompt: user inputing 20150315

where Mon = 03 and day = 15..

Fiscal start and end date are based out of fiscal calendar derived in webi.. where start date = 3/1/15 and end date = 4/4/15

no what i would be wanted is to write an logic of Mon and Day to be compared to fiscal start and end date and derive my fiscal period which is 003/2015

if my input date is 20150228 = the report header should display 002/2015 and if

my input is 20150315 = = the report header should display 003/2015

there would be cases of start and end date differ for each fiscal calnedar and date input is dynamic now how can i arrive this to display which fiscal period in my report header

if user doesnt input anything last execution date base to derive the fiscal period by lookup up the snapshot table..

Thanks,

Dinya