I would suggest you to read the document I have written a few time ago:
It explains, in the script, how to populate an Asof table, which will be used to do the rolling cumultative datas, the YTD etc. it should answer to your question.
Thanks for your reply, but i want some thing like below.
say we have 30 weeks data , from 13th week we should sum up the Previous data(EX: 13th week 1-13 , 14th week 2-14 15th week 3-15..and so on). hope you understand my requirement. and i need to this in LOAD Script level not in report level.
Thanks & Regards,