Delete Duplicate Records Using Common Tabel Expression

there are many ways to delete the duplicates in a table but sometimes the group by doesnt seem to work so you can try out the new feature of Microsoft SQL Server "Common Table Expression"

With Dups as 

(

SELECT  row_number() over (

partition by ColumnName 

order by  ColumnName ) as RowNum

FROM Table

)

DELETE 

FROM Dups 

WHERE rownum > 1