This will trim off unwanted characters from the both sides of string.
Syntax: trim (unwanted_chars from string)
Ex:
SQL> select trim( 'i' from 'indiani') from dual;
TRIM(
-----
ndian
SQL> select trim(
leading'i' from 'indiani') from dual; --
this will work as LTRIM
TRIM(L
------
ndiani
SQL> select trim(
trailing'i' from 'indiani') from dual; --
this will work as RTRIM
TRIM(T
------
Indian