mysql 날짜 가감 계산
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 YEAR);
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 MONTH);
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 DAY);
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 HOUR);
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 MINUTE);
SELECT DATE_ADD("1997-12-31 23:59:59", INTERVAL 10 SECOND);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 YEAR);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 MONTH);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 DAY);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 HOUR);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 MINUTE);
SELECT DATE_SUB("1997-12-31 23:59:59", INTERVAL 20 SECOND);