substr instr length for loop - plsql

Question

good morning guys i have a problem with code i work on Health Care and complain code must be checkbox but they ask for Report that contain the treatment code which is gonna appear in database like this 1:15:2:3 etc so i need to calculate each code separate
i have to count until i get ":" then i need to take the number which can be 1 or 2 digit then making inner join with the other table
can anyone help me to fix this function and the problem in the loop and get the number for each one
create or replace function hcc_get_tcd_codes (p_id in number )
return varchar2 is
x number := 0 ;
y number := 0 ;
z number ;
code1 number ;
code_name varchar2(15);
begin
for i in 0 .. x
loop
select length(t.tcd_codes ) into x from hcc_patient_sheet t where t.id = p_id ; --- (9)العدد كامل
select instr(tcd_codes, ':') into y from hcc_patient_sheet t where t.id = p_id ; ---- عدد الكود الاو(3)ل
select instr(tcd_codes, ':')+1 + y into z from hcc_patient_sheet t where t.id = p_id ; --عدد الكود كامل +1
enter code here
i := x -y ;
select substr(t.tcd_codes,z, instr(tcd_codes, ':')-1) into code1
--,select substr(t.tcd_codes, 0, instr(tcd_codes, ':')-1) as code2
from Hcc_Patient_Sheet t
where t.id = 631 ;
select t.alt_name into code_name from hcc_complaint_codes t where t.code = code1 ;
select instr(tcd_codes, ':') into y from hcc_patient_sheet t where t.id = p_id ; ---- عدد الكود الاول
return code_name ;
end loop ;
end;

Answer 1

Often with frequent sounding string processing issues, a wheel has already been invented, and even packaged.
select * from table(apex_string.split('THIS:IS:GREAT',':'));

Answer 2

Partial SUBSTR doesn't seem to be the best option; I'd suggest you to split that colon-separated-values string into row as follows:
SQL> with test (col) as
2 (select '1:15:2:3' from dual)
3 select regexp_substr(col, '[^:]+', 1, level) one_value
4 from test
5 connect by level <= regexp_count(col, ':') + 1;
ONE_VALUE
--------------------------------
1
15
2
3
SQL>
and use such an option in your query; something like this:
select ...
into ...
from some_table t
where t.id in (select regexp_substr(that_string, '[^:]+', 1, level) one_value
from dual
connect by level <= regexp_count(that_string, ':') + 1
);
If it has to be row-by-row, use the above option as a source for the cursor FOR loop, as
for cur_r in (select regexp_substr(that_string, '[^:]+', 1, level) one_value
from dual
connect by level <= regexp_count(that_string, ':') + 1
)
loop
do_something_here
end loop;