create table items (id raw(16), text clob, geom sdo_geometry )

select 
sum(token_count) as wordcount, 
TOKEN_TEXT as word
from DR$ITEMS_NAME_IDX$k a
inner join items b on a.textkey = b.rowid
inner join ??? 
where sdo_relate(b.geom,PARAM_GEOMETRY)='TRUE'
group by TOKEN_TEXT;

Well, you don't need to use Oracle Text indexes to do this at all!

Using standard SQL there are various words-to-rows techniques. For example, if you have simple, single spaced text, you can find the number of words by subtracting the length of the text from itself with the spaces removed. And adding one.

You can then use the "connect by level" row generation trick to convert these to rows and count them up. The introduction of lateral in 12c made this a easier:

create table t (
  x varchar2(100)
);
insert into t values ('some text more text extra text some more text');
commit;
select 
  trim(regexp_substr(t.x, '[[:alpha:]]+', 1, words.l)) word,
  count(*)
from t,
     lateral (
       select level l from dual 
       connect by level <= length (t.x) - length(replace(t.x, ' ')) + 1 
     ) words
group by trim(regexp_substr(t.x, '[[:alpha:]]+', 1, words.l))
order by count(*) desc;

WORD    COUNT(*)   
text             4 
some             2 
more             2 
extra            1 

Of course, this will find all the words. One advantage of Oracle Text Oracle Text is you can use a stoplist to exclude common words (as, and, of, etc.)

But again, you don't actually need to create a text index to do this. You can pass the string you want to tokenize to ctx_doc.policy_tokens. This splits the string up to words.

All you need to do then is aggregate the results:

exec ctx_ddl.create_policy('mypolicy');
declare
  la     varchar2(200);
  rtab   ctx_doc.token_tab;
begin
   ctx_doc.policy_tokens('mypolicy', 
        'some text more text extra text some more text',rtab);
   for words in (
     select token, count(*) c from table(rtab)
     group  by token
     order  by count(*) desc
   ) loop
     dbms_output.put_line(words.token || ' count = ' || words.c);
   end loop;
end;
/

TEXT count = 4
MORE count = 2
EXTRA count = 1

Some is in the default stoplist. So it's no longer included in the output.