I ran into a problem recently where I needed to delete all rows in a MySQL table that were older than three months. This I was able to accomplish with the following statement:
DELETE FROM [table] WHERE [column] < DATE_SUB(NOW(), INTERVAL 3 MONTH);
Substitute table and column, and a proper date option. The date_sub function subtracts a time period from the date specified. In this statement, NOW() grabs the current date from which INTERVAL 3 MONTHS is subtracted (along with the < operand).