ORACLE 遍历字符串解决思路

ORACLE 遍历字符串
假如有个字符串"abcde"
ORACLE中怎样才能返回一个循环拿到每一个字符也就是"a","b","c"....其中全角半角都有可能出现

------解决方案--------------------
select substr('abcdef', rownum, 1) data1
from dual
connect by rownum <= length('abcdef')

9i才可以