ADD_MONTHS vs INTERVAL - forum topic by bikky6

Please let me know the exact difference between using INTERVAL and ADD_MONTHS
SEL CAST('2013-08-29' AS DATE ) -INTERVAL '6' MONTH
returns Invalid Date

SEL ADD_MONTHS(CAST('2013-08-29' AS DATE ),-6)
returns 2013-02-28
Regards
KVB