CREATE UNIQUE NONCLUSTERED INDEX UX_TableName_Field ON dbo.TableName(Field)
 WHERE Field IS NOT NULL;

SELECT [Name]
     , COUNT(*) AS 'RowCount'
     , SUM(LineTotal) AS 'TotalValue'
  FROM Production.Product P
  JOIN Sales.SalesOrderDetail D ON D.ProductID = P.ProductID 
  GROUP BY ProductID 

SELECT [Name]
     , COUNT(*) AS 'RowCount'
     , SUM(LineTotal) AS 'TotalValue'
  FROM Production.Product P
  JOIN Sales.SalesOrderDetail D ON D.ProductID = P.ProductID 
  GROUP BY [Name]