Add_months function returns a DATETIME value – that adds ‘n‘ number of months from the input date provided.

The syntax of ADD_MONTHS function is:  ADD_MONTHS (input_date, n) where:

• input_Date – is the date from which the function is to be applied on.
• n – n is the integer value of number of months to add from the input date

SELECT ADD_MONTHS (SYSDATE, 10) FROM DUAL;

(Sysdate is: 10/29/2018 7:52:53 PM)

Logic: Adds 10 months to the sysdate

Result: 8/29/2019 7:52:53 PM

SELECT ADD_MONTHS (SYSDATE, -10) FROM DUAL;

(Sysdate is: 10/29/2018 7:53:46 PM)

Logic: Adds 10 months to the sysdate

Result: 12/29/2017  7:53:46 PM