>I have a table with transactional records, and each record has a start and an end date. I am creating a SPROC to insert a record into this table, but I want to make sure that the start date and end date in the record I am inserting does not overlap any of the date ranges in any records in the table.

-- @StartDate and @EndDate are dates for new record
IF NOT EXISTS (SELECT * FROM mytable 
		WHERE @StartDate BETWEEN StartDate AND EndDate
			OR @EndDate BETWEEN StartDate AND EndDate)
	INSERT INTO ...