-- Get the number of days in a certain period and the season price
set @start = "2007-07-10";
set @end = "2007-08-10";
select 		s_date_end
			,s_date_start
			,s_id
			,sp_price
			,sp_id
			,sp_price
			,sp_interval
			,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 -- put this in a variable
			, @number_of_days  * fieldname -- is this possible?
from 		seasons
inner join	season_prices
	on		sp_seasonsid = s_id
where		TO_DAYS(@start) < TO_DAYS(s_date_end)
and			TO_DAYS(@end) > TO_DAYS(s_date_start);