Setup variables for BEx Query

Question

Dear all,
I am working on a BEx query. I would like to show MTD and YTD actual & planned expenses. My questions are as follows:
(1)      how can I set up variables or variants which can look up the system date to calculate the MTD and YTD date? For example, I execute the query without input the date and I would like the query automatically look up the date for YTD  (e.g. 1/1/2009 u2013 2/20/2009) and MTD (2/1/2009 u2013 2/20/2009) for actual expenses?
(2)     Since the planned data is by year and distribute 12 months equally and not by day, how can I set up variables which can look up the system date to calculate the number of the days from the beginning of the year up to today and beginning of the month update to today so I can calculate the MTD and YTD planned expenses based on the annual budget.
Thanks

Answer 1

Thanks Reddy,
Since my variable for planned data is not date variable anymore, it is a factor = current date / number of days in current month and I used this to multiple by the planned monthly data.  If I used entire month and  the plan data will be overvalue, I can't compare to the MTD actual data since actual date is updated by day.  How can I create a variable for this and use it to caluclate in the BEx Query?
I believe the function will work but I don't know much about ABAP.  I try to search sample code for the function.  here is what I get but I don't think it is going to work. Can you point out what is missing? I believe I need to put it under 'ZXRSAU01'
Under CASE I_DATASOURCE
I put
WHEN 'ZMTDFACTOR'. #the variable name of the MTD factor
PERFORM ZMTDFACTOR_EXIT.
In ZMTDFACTOR_EXIT  and here is the code I get so far
WHEN 'ZMTDFACOTR'.
    DATA:  SDT TYPE SY-DATUM,
          MON_FACTOR TYPE N,
          ST_CD(2) TYPE N,   
          ST_LD(2) TYPE N.     
            l_date_in  type sy-datum,
            l_date_out type sy-datum.
          SDT = SY-DATUM.
*current date
          ST_CD = SDT+6(2).
CONCATENATE l_v_calmonth '01' into l_t_range-low.
l_date_in = l_t_range-low.
CALL FUNCTION 'SLS_MISC_GET_LAST_DAY_OF_MONTH'
  EXPORTING
    day_in                  = l_date_in
IMPORTING
   LAST_DAY_OF_MONTH       = l_date_out
EXCEPTIONS
   DAY_IN_NOT_VALID        = 1.
*last date
ST_LD = l_date_out+6(2).
*Calculate the factor based on the MTD
MON_FACTOR = ST_CD / ST_LD.
How can I send MON_FACTOR to ZMTDFACOTR and back to the query?
Thanks again.