CREATE TABLE #t (
  product_name nvarchar(20), 
  vendor_name nvarchar(20)
)
GO
INSERT INTO #t (product_name, vendor_name)
SELECT 'SQL Server', 'Microsoft' UNION ALL
SELECT 'Oracle', 'Oracle' UNION ALL
SELECT 'DB2', 'IBM' UNION ALL
SELECT 'Oracle', 'Oracle' UNION ALL
SELECT 'Oracle', 'Oracle' UNION ALL
SELECT 'DB2', 'IBM'  UNION ALL
SELECT 'DB2', 'IBM' UNION ALL
SELECT 'DB2', 'IBM'
GO
 
SELECT * FROM #t;
 
DECLARE @col1 nvarchar(255), @col2 nvarchar(255), @dup_count int;
WHILE 1 = 1 BEGIN
  SELECT TOP 1 @col1 = product_name, @col2 = vendor_name, @dup_count = COUNT(1) - 1
  FROM #t
  GROUP BY product_name, vendor_name
  HAVING COUNT(1) > 1
  IF @@ROWCOUNT = 0 BREAK;
  DELETE TOP (@dup_count) FROM #t WHERE @col1 = product_name AND @col2 = vendor_name;
END
 
SELECT * FROM #t;
GO
 
DROP TABLE #t