oracle正则反向引用:SELECT REGEXP_REPLACE('aaa,bb,cc' , '([[:alpha:]]+),([[:alpha:]]+),([[:alpha:]]+)', '\2') FROM DUAL;
Select REGEXP_REPLACE('aaa,bb,cc','(.*),(.*),(.*)', '2') FROM dual; select regexp_substr('aaa,bb,cc', '[b]+') from dual;都行的