SUBTRACT MONTHS in Teradata

Using the ADD_MONTHS functionality you can subtract the months.

Syntax:
SELECT ADD_MONTHS('YYYY-MM-DD' , -n)


Example:
Subtracting 2 months
SELECT ADD_MONTHS ('2000-08-15' , -2);

Result: 2000-06-15

Subtracting 1 month
SELECT ADD_MONTHS ('2000-09-30' , -1);

Result: 2000-08-30