Compare variable to a value in a query - oracle

Question

I have a cursor that I need to loop through and check a couple conditions. If the person's category is greater than 24, I need it to then see if the person also had a previous record in the table and change the value of the v_check variable if it meets the conditions. The problem is it is saying I can't use a query here. How could I pull this off?
[Error] Compilation (248: 39): PLS-00405: subquery not allowed in this context
IF v_category > 24 THEN
IF v_person_id = (
SELECT person_id
FROM mytable
WHERE category = 24
AND outcome IS NULL
AND person_id = v_person_id
) THEN v_check := 'NO PREV OUTCOME';
ELSIF v_person_id = (
SELECT person_id
FROM mytable
WHERE category = 24
AND outcome_date IS NULL
AND person_id = v_person_id
) THEN v_check := 'NO OUTCOME DATE';
ELSIF category = 24 THEN v_check := 'N/A';
END IF;
ELSE v_check := 'OK';
END IF;

Answer 1

Main problem is that you can't use a subquery that way; first find value(s) returned by the select statement(s), then use them in case.
Also, code you posted doesn't make much sense as
you use v_person_id as a variable (to store a value into) and - at the same time - in select's where clause
the first if checks whether v_category > 24, while the last elsif says that if v_category = 24 then 'N/A' - that's never going to happen.
Here's an example which show how to do it; it probably won't work because I don't know what exactly you want to do (because of notes I posted above), but I hope that it'll get you started.
declare
v_person_id number := some value
l_person_id number;
l_person_uid number;
begin
select person_id, person_uid
into l_person_id, l_person_uid
from mytable
where category = 24
and outcome is null
and person_id = v_person_id;
v_check = case when v_category > 24 and v_person_id = l_person_id then 'NO PREV OUTCOME'
when v_category > 24 and v_person_id = l_person_uid then 'NO OUTCOME DATE'
else 'N/A'
end;
end;