trimming leading characters I'm in oracle and I have a table 'parts' in which have a field 'Description', which contains description for a part.
my query is:

SELECT DESCRIPTION
FROM   PART
WHERE  PAR_ID=123
AND    DESCRIPTION LIKE 'CHARGE BATTERIES%';


it results:

CHARGE BATTERIES
CHARGE BATTERIES_3
CHARGE BATTERIES_4


I want it to only result '3' and remove all leading characters.
I'm familiar with sql trim, substr ans instr functions but don't know hot use these functions.
Any help will be appreciated.
SELECT to_number(replace(DESCRIPTION, rtrim(DESCRIPTION, '0123456789')))
FROM   PART
WHERE  PAR_ID=123
AND    DESCRIPTION LIKE 'CHARGE BATTERIES%';


When there is no number at the end it will result NULL. If you want to have zero then use:

SELECT nvl(to_number(replace(DESCRIPTION, rtrim(DESCRIPTION, '0123456789'))), 0)
FROM   PART
WHERE  PAR_ID=123
AND    DESCRIPTION LIKE 'CHARGE BATTERIES%';