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.

Answer 2

The way I see it, nothing of what you want will happen. Bad news, eh?

Code you wrote is wrong - not because of obvious mistakes, but - cursor's SELECT statement contains 3 columns which you're fetching into a 1 varchar2 variable. 3 can't fit into 1; not that way, that is.

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Moreover, what would you do with a loop within the function? It can be done, of course, for example (switching to cursor FOR loop for simplicity), but - depending on where you put RETURN, you'll either return the first O_RESULT value or the last (see comments within the code):

for cur_r in (select sprhold_hldd_code, ...
              from sprhold ...
              where --> ID condition missing here; ID you're passing, allegedly
             )
loop
  if cur_r.sprhold_hldd_code in ('TL', 'TY', ...) then ...
     -- in a number of IFs, you find what O_RESULT variable is
  end if;

  -- if you put RETURN here, only one loop iteration will execute

end loop;

-- if you put RETURN here, only the last O_RESULT value will be returned

---

It means that you'd actually want to put a loop OUTSIDE of the function, i.e. call the function in a loop for all those IDs you're about to pass to the function. Something like this:

function f_result (par_id in number) return varchar2 is
  o_result varchar2(20);
begin
  select sprhold_hldd_code
    into l_sprhold_hldd_code
    from sprhold ...
    where some_id = par_id;

  if l_sprhold_hldd_code in ...
     -- find O_RESULT in a number of IFs
  end if;

  return o_result;
end;

Now call it in a loop

begin
  for cur_r in (select id from some_table where some_condition) loop
    dbms_output.put_line('For ID = ' || cur_r.id || ', function returned ' || f_result(cur_r.id));
  end loop;
end;

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If none of above helps, try to rephrase the question.