Question

Is it possible to use subqueries in the OPTIONS parameter table for the RFC_READ_TABLE in SAP?

Something like this

field in (select otherfield from othertable where ...)

Answer 1

No. Specifying an OPTIONS parameter which contains parentheses will cause an error (ABEND dump).

From the SAP doco (4.6C):

WHERE (itab) 

The internal table itab may only have one field. This must have type C,
and may not be longer than 72 characters. You must specify itab in
parentheses, without a space between the parentheses and the table name. 
The condition contained in the internal table must have the same form as
a corresponding condition in the ABAP source code. The following
restrictions apply: 
- You can only use literals as values, not variables. 
- You cannot use the IN operator in the form f1 IN itab1. 
The internal table itab may be empty.