Variable default values

Hi Experts,

I am using a variable for Date From to Date to in my Query. I had used the variable 0I_SPL_D which supplies two date Period from / Period To. My requirement is to give default values at run time from beginning of the month to current date of execution.

So that I can schedule the Query and Broadcast it.

eg If the report is run today ie on 22.0ct.2009 then both the ends must have the values

from date 01.10.2009 and

to date 22.10.2009

If the report is executed tomorrow the parameters should be

from date 01.10.2009 and

to date 23.10.2009

can any one give any idea

Thanks

Shivani