substr from a field value oracle code example

Example 1: ORACLE SQL SUBSTR

SUBSTR(string, :START_POS, :SUBSTR_LENGTH);

SELECT SUBSTR('ABCDEFG',3,4) FROM DUAL;
--OUTPUT: CDEF

Example 2: oracle right characters

-- For Oracle only

-- syntax 
SUBSTR(<main-string>,-<number-of-characters>)

-- example 
SUBSTR('Useless stuff',-9) -- OUTPUT: ess stuff

-- practical example
SELECT SUBSTR('Useless stuff',-9)
FROM DUAL;