[OBIEE11g] Getting 30days back data from the selected date in dashboard prompt

1) Create a prompt day week and declare presentation variable

2) Here is the report ,i pulled product and booked qty

To show 30days back booked quantity the date selected in prompts

In fx use

FILTER("Facts Other"."Booked Qty" USING (Time."Day Date"=TIMESTAMPADD(SQL_TSI_DAY, -30, DATE '@{day}')))

You can apply the same formula for 1....n days

For month level use
FILTER("Facts Other"."Booked Qty" USING (Time."Day Date"=TIMESTAMPADD(SQL_TSI_MONTH, -3, DATE '@{month}')))

where -3= three months back