SELECT 
	my_date + (
		CASE 
			WHEN 
				my_date BETWEEN 
					next_day(to_date( extract(YEAR FROM my_date)||'0324','YYYYMMDD'), 'Sunday') 
				AND 
					next_day(to_date( extract(YEAR FROM my_date)||'1024','YYYYMMDD'), 'Sunday')
			THEN 
				2 
			ELSE 
				1 
		END
	)/24 
FROM 
	my_table;