;with cte (sku,[date],price) as (
select 1,'20180101',2
union all
select 1,'20180102',2
union all 
select 1,'20180103',2
union all 
select 1,'20180104',3
union all
select 1,'20180105',3
union all
select 1,'20180106',2
union all
---
select 2,'20180101',2
union all
select 2,'20180102',2
union all 
select 2,'20180103',2
union all 
select 2,'20180104',3
union all
select 2,'20180105',3
union all
select 2,'20180106',2
union all
select 2,'20170104',2 -- especial

)
, tot (rn,date,price,sku) as
(select ROW_NUMBER() over(order by sku,date) rn -- root of evil :)
		,date
		,price
		,sku
from cte)
select t1.sku
		,t1.date	
		,t1.price
		
from tot t1 
left join tot t2 
on t2.rn=t1.rn-1 
	and t1.price=t2.price 
	and t1.sku=t2.sku
where t2.rn is null