select regexp_substr(‘a-b-c-d-e’,'(.)-(.)-(.)-(.)-(.)’,1,1,null,3) from dual;
R
-
c

unfortunately, the following does not work

select regexp_substr(‘a-b-c-d-e’,'(.)-(.)-(.)-(.)-(.)’,subexpression=>3) from dual;
select regexp_substr(‘a-b-c-d-e’,'(.)-(.)-(.)-(.)-(.)’,subexpression=>3) from dual
*
ERROR at line 1:
ORA-00907: missing right parenthesis

and the workaround to use full qualification have the side effect of not recognizing the max length of

select sys.standard.regexp_substr(‘a-b-c-d-e’,'(.)-(.)-(.)-(.)-(.)’,subexpression=>3) from dual;
SYS.STANDARD.REGEXP_SUBSTR(‘A-B-C-D-E’,'(.)-(.)-(.)-(.)-(.)’,SUBEXPRESSION=>3)
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c

Cheers,
Laurent