Question

A)

select decode(count(*), 0, 'N', 'Y') rec_exists
from (select 'X'
      from dual
      where exists (select 'X'
                    from sales
                    where sales_type = 'Accessories'));

B)

select decode(count(*), 0, 'N', 'Y') rec_exists
from (select 'X'
      from sales
      where sales_type = 'Accessories'); 

C) Something else (specify)

EDIT: It was hard to pick the “correct” answer, as the best approach depends on what you want to do after checking if the value exists, as pointed out by APC. I ended up picking the answer by RedFilter, since I had originally envisioned this check as a function by itself.

Answer 1

select case 
            when exists (select 1 
                         from sales 
                         where sales_type = 'Accessories') 
            then 'Y' 
            else 'N' 
        end as rec_exists
from dual;