Hi Harish,
I think you should check your function module.
When datasource uses a function module you need to include the field(s) that you want to be available in the selection criteria(in this case : CREDAT) in following parts of the code.
For Eg :
RANGES: l_r_credat FOR <name of the table>-credat.
LOOP AT s_s_if-t_select INTO l_s_select WHERE fieldnm = 'CREDAT'.
MOVE-CORRESPONDING l_s_select TO l_r_credat.
APPEND l_r_credat.
ENDLOOP.
OPEN CURSOR WITH HOLD s_cursor FOR
SELECT *
FROM <name of the table>
WHERE ( condition ) AND
credat IN l_r_credat.
Try to change this code and extract records in RSA3 with CREDAT = 19.03.2015
Hope this helps.
Regards
Sakshi