ID Min Max
10 400 500 
20 350 470 
30 480 520 
40 460 540
50 310 360

Base ID Min  Max
 10  20 400  460
 10  40 460  500 

set nocount on
Declare @tb Table ([id] int, [min] int, [max] int)
insert @tb
Select 10, 400, 500 UNION ALL
SElect 20, 350, 470 UNION ALL 
Select 30, 480, 520 UNION ALL
Select 40, 460, 540 UNION ALL
Select 50, 310, 360 


Select	base = bg.[id]
	,a.[id]
	,[min] = case when a.[min] < bg.[min] then bg.[min] else a.[min] end
	,[max] = case when a.[max] < bg.[max] then a.[max] else bg.[max] end
From	
	--Get the background record
	(SElect	[id], [min], [max] from @tb where [id] = (Select min([id]) from @tb)) bg

JOIN	@tb a
		--limit results to ranges that overlap the background
		ON bg.[min] <= a.[max] AND bg.[max] >= a.[min]

Left JOIN 	(--Get all previous records that are completely obsured by current record
		Select y.[id]
		From	@tb z
		JOIN	@tb y
			ON 	--only previous records
				y.[id] < z.[id]
			AND 
				--only records completely obscured
				y.[min] >= z.[min] AND y.[max] <= z.[max]
		) as obscured
		ON a.[id] = obscured.[id]

--exclude the background record from results
Where	a.[id] <> bg.[id]

--exlcude previous completely obscured records
AND	obscured.[id] is NULL