mySQL Comandos Fechas

Trabajo con fechas:

mysql> SELECT DATE_ADD('2009-03-20', INTERVAL 31 DAY);
mysql> SELECT DATE_ADD('2009-03-20', INTERVAL 1 MONTH);
mysql> SELECT ADDDATE(CURDATE(), INTERVAL 31 DAY);
mysql> SELECT SUBDATE(CURDATE(), INTERVAL 2 MONTH);

La palabra clave INTERVAL y el especificador type no son sensibles a mayúsculas.

La siguiente tabla muestra cómo se relacionan los argumentos type y expr :

type Value	Expected expr Format
MICROSECOND	MICROSECONDS
SECOND	SECONDS
MINUTE	MINUTES
HOUR	HOURS
DAY	DAYS
WEEK	WEEKS
MONTH	MONTHS
QUARTER	QUARTERS
YEAR	YEARS
SECOND_MICROSECOND	'SECONDS.MICROSECONDS'
MINUTE_MICROSECOND	'MINUTES.MICROSECONDS'
MINUTE_SECOND	'MINUTES:SECONDS'
HOUR_MICROSECOND	'HOURS.MICROSECONDS'
HOUR_SECOND	'HOURS:MINUTES:SECONDS'
HOUR_MINUTE	'HOURS:MINUTES'
DAY_MICROSECOND	'DAYS.MICROSECONDS'
DAY_SECOND	'DAYS HOURS:MINUTES:SECONDS'
DAY_MINUTE	'DAYS HOURS:MINUTES'
DAY_HOUR	'DAYS HOURS'
YEAR_MONTH	'YEARS-MONTHS'

Referencias:
http://dev.mysql.com/doc/refman/5.0/es/date-and-time-functions.html