Oracle query to find all occurrences of a charcter in a string

Question

I have to write an Oracle query in toad to find all the occurrences of a character in a string. For example if I\'m searching for R in the string SSSRNNSR

Answer 1

To take up a_horse_with_no_name's challenge here is another answer with a pipelined table function.

A pipelined function returns an array, which you can query normally. I would expect that over strings with large numbers of matches this will perform better than the recursive query but as with everything test yourself first.

create type num_array as table of number
/


create function string_indexes (
    PSource_String in varchar2
  , PSearch_String in varchar2
    ) return num_array pipelined is

begin

   for i in 1 .. length(PSource_String) loop

      if substr(PSource_String, i, 1) = PSearch_String then
         pipe row(i);
      end if;

   end loop;

   return;

end;
/

Then in order to access it:

select *
  from table(string_indexes('SSSRNNSRSSR','R'))

SQL Fiddle