Need for customer exit code to go to previous date

Question

In the ODS there is a date which is a user entry on my report. I need to write a customer exit which goes to previous date.
In other words let's say user entered 07/07/07 at the user entry, and there is no activity for the entered date. The previous activity date in ODS data is 07/05/07. The report should run based on the previous date. ( Date is the key by the way )
I will appreciate any help with points,
Regards,
Mike

Answer 1

I just wrote this quickly and I limited to 10 loops because something is wrong if it is further back than that and I think another solution should be done.  This is also assuming the volume of data is not too large.  If so you may want to take the year off the date and add that to the select statement.
Can the previous date be any date?  So lets say the user entered 07/07/07 and the last activity was 01/01/07?  Is date the only key? 
If so you can do something like this.
date_ 1 like <date_ field in ODS>
date_ 2 like <date_ field in ODS>
counter(2) type n
  DATA:    BEGIN OF data_all OCCURS 0,
             Date_ 3 like date_ 1
           END OF data_all
date_ 1 = user enter
counter = 10
Select <date_ field> from <ods backend table> into data_all
Sort ascending
While counter > 0
   Read data all where data_all-date_3 = date_1
If sy-subrc <> 0
  Date_ 1 = date_ 1 – 1
Counter = counter - 1
Continue.
Else
date_2 = date_1
Exit.
Endif
End loop
Return date_2