select regexp_substr('1,2,3' , '[^,]+' , 1 , ROWNUM) FROM dual CONNECT BY ROWNUM<=LENGTH('1,2,3')-LENGTH(regexp_replace('1,2,3' , ',' , '') )+1;
select regexp_substr('1,2,3' , '[^,]+' , 1 , ROWNUM) FROM dual CONNECT BY ROWNUM<=LENGTH('1,2,3')-LENGTH(regexp_replace('1,2,3' , ',' , '') )+1;