×Ö·ûº¯Êýlpad,rpad,ltrim,rtrim,substrʹÓÃ

select lpad('abc', 5, '#') leftpad,
rpad('abc', 5, '#') rightpad,
ltrim('abcd', 'a') lefttrim,
rtrim('abcde', 'e') righttrim,
substr('abcd', 2, 3) substring
from dual