can i write a loop inside a function that has if then else if conditions?

Question

content : i am writing a function to return a value based on 3 conditions, but i need to write a loop inside it so it can check the conditions for each id passed. can i write t

Answer 1

It is hard for us to reverse engineer business logic from broken code. It is easier to understand clearly stated rules. So this is my interpretation of what you want:

For a given id:

1. return level 1 if it has distinct codes matching only ('TF','TB','TY','TL','TS')
2. return level 2 if it has other codes not matching ('TF','TB','TY','TL','TS')
3. return level 3 if it has null codes
4. else return level 4 (e.g. when NO_DATA_FOUND)

create or replace FUNCTION          fwt_get_holds(
    i_id  id.table_im%TYPE
) RETURN VARCHAR2 IS
    l_level1 number := 0;
    l_level2 number := 0;
    l_level3 number := 0;
    l_level4 number := 0;
BEGIN 
  begin
    SELECT count(case when sprhold_hldd_code in ('TF','TB','TY','TL','TS') then 1 end ) as lvl_1
           , count(case when sprhold_hldd_code LIKE 'T%' and sprhold_hldd_code not in ('TF','TB','TY','TL','TS') then 1 end ) as lvl_2
           , count(case when sprhold_hldd_code is null then 1 end ) as lvl_3
    into l_level1
         , l_level2
         , l_level3
      FROM sprhold,
           stvhldd
      WHERE stvhldd_code = sprhold_hldd_code
      AND sprhold_to_date >= trunc(sysdate)
      AND sprhold_pidm = i_id;
    exception
      when others then 
        l_level4 := 1;
   end;
   if l_level4 != 0 then 
      return 'level 4';  -- no data found ?
   elsif l_level3 != 0 then 
      return 'level 3';  -- found some nulls
   elsif l_level2 != 0 then 
      return 'level 2';  -- found some non-matching codes
   else
     return 'level 1';   -- found only matching codes
  end if; 
END fwt_get_holds;

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Quite possibly this is not what you want. If so, I suggest you edit your question to explain your business rules, as I did at the top of this answer.