Delete Or Change Records In Etl

I have a table over which I have built an ETL service. Goods records (arrival / departure) go to the table. I have done that my table will be erased. When the item identifier arriv

Solution 1:

To meet both your requirements you should check for change in cost like below

 ; with todelete as (
      select *, 
           count(*) over (partition by label) as cnt, 
           lag(cost) over (partition by label order by time ASC) as lastcost
           ROW_NUMBER() over (partition by label order by time ASC) as r_number
      from Table1
     )
delete from todelete 
    where cnt > 1 and r_number between 1 and (cnt/2)*2 and  cost=ISNULL(lastcost,cost)