How to validate a parameter value using Special value set.

After selecting SPECIAL validation type go to edit then select validate in the list write the code as mentioned below. Below code is used to validate the value based on the other parameter value.

FND PLSQL 

"declare

 l_diff NUMBER := 0;

l_to_Date varchar2(30) := :!VALUE;

l_from_date varchar2(30) := ':$FLEX$.XXG_ACC_TRX_FROM_DATE.VALUE';

begin

if to_date(l_from_date)<to_date(l_to_date) then

l_diff := (to_date(l_to_date) - to_date(l_from_date));

if l_diff > 35 then

   fnd_message.set_name( 'FND', 'FND_GENERIC_MESSAGE' ) ;

fnd_message.set_token( 'MESSAGE', 'Date Range Exceeded 35 days.' );

fnd_message.raise_error ;

end if;

else

fnd_message.set_name( 'FND', 'FND_GENERIC_MESSAGE' ) ;

fnd_message.set_token( 'MESSAGE', 'To date should be greter than from date.' );

fnd_message.raise_error ;

end if;

end; "