select now();
# 2012-01-11 09:46:46
select curdate();
# 2012-01-11
select date('2012-01-11');
# 字符串转date类型
select date_format('2012-01-11','%Y%m%d');
# 字符串转date类型
更多命令:
http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html
--heipark