Menghapus Duplikat Data SQL Server 2008

Menghapus Duplikat data key 

WITH CTE AS(
SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],
RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1)
FROM table)
DELETE FROM CTE WHERE RN > 1