如何构造SQL子查询？

select
e.EMPNO,
e.ENAME
from  
emp e
where 
e.DEPTNO in  (select case
                      when 'D'='D'  then q'[10,20]'
                       END DPT 
                  from dual )
select
e.EMPNO,
e.ENAME
from  
emp e
where 
e.D