Use the NOW() function to obtain the current system date and time as a datetime value.
NOW()
The current system date and system time is returned as a datetime value.
For more information on obtaining only the current system date, see TODAY().
Using a current system date of Aug 22, 2013 and a current system time of 7:57:03 p.m.:
DAY(NOW()) = 22
MONTH(NOW()) = 8
YEAR(NOW())= 2013
HOUR(NOW()) = 19
MINUTE(NOW()) = 57
SECOND(NOW())= 3