CREATE TABLE `seasons` (
  `s_id` int(11) unsigned NOT NULL auto_increment,
  `s_name` varchar(255) NOT NULL,
  `s_date_start` date NOT NULL,
  `s_date_end` date NOT NULL,
  `s_date_created` datetime NOT NULL,
  `s_date_changed` datetime NOT NULL,
  `s_created_by` int(11) unsigned NOT NULL,
  `s_changed_by` int(11) unsigned NOT NULL,
  PRIMARY KEY  (`s_id`)
) ENGINE=MyISAM

-- get the number of days per period
set @start = "2007-03-10";
set @end = "2007-09-10";
select 	*,
		TO_DAYS(s_date_end) AS todays_end
		,TO_DAYS(s_date_start) AS todays_start
		,TO_DAYS(LEAST(s_date_end, @end)) - TO_DAYS(GREATEST(@start, s_date_start)) AS number_of_days_in_season
from 	seasons
where	TO_DAYS(@start) < TO_DAYS(s_date_end)
and		TO_DAYS(@end) > TO_DAYS(s_date_start)