Question : basic physics - reflection versus refraction

Hi

I believe reflection occurs when light bounces off a surface and refraction occurs when light travels through a surface with a change of direction. Does the definition of refraction include the notion of a change of direction? I think it does. If so, what is it called, if anything when light passes through a material without a change in direction e.g. when both materials have the same refractive index

thanks

Answer : basic physics - reflection versus refraction

instead of union and while just use

year(h.ivh_deliverydate) between @yearFrom and @yearTo

                       
         
           
           
             declare @year int, @month int
set @yearFrom = 2009
set @yearTo = 2011
set @month = 06
begin
select 
	h.ivh_revtype1, 
	@month, @year,
	'Line Haul',
	(select sum(i.ivd_charge)) 
from invoicedetail as i inner join invoiceheader as h on i.ivh_hdrnumber = h.ivh_hdrnumber
where month(h.ivh_deliverydate) = 06 and i.cht_itemcode like 'LH%' and
	year(h.ivh_deliverydate) between @yearFrom and @yearTo 
group by h.ivh_revtype1

end
           
         