Option 1:

WITH CTE AS(

SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],

RN = ROW_NUMBER()OVER(PARTITION BY [col1], [col2] ORDER BY [col1], [col2])

FROM dbo.Table1

)

DELETE FROM CTE WHERE RN > 1

Option 2:

DELETE FROM dbo.TABLE WHERE AUTOID NOT IN (SELECT MIN(AUTOID)

FROM dbo.TABLE GROUP BY Col1, Col2)

Option 3:

SET ROWCOUNT 1

DELETE FROM dbo.duplicateTest WHERE ID = 1

SET ROWCOUNT 0

Option 4:

DELETE TOP(1) FROM dbo.duplicateTest WHERE ID = 1