SQL(Careate Function)

CREATE FUNCTION dbo.Portal_fnGetRestaurantRating (@CustomerId bigint)

RETURNS int

AS

BEGIN

      DECLARE

            @value int

SELECT @value = IsNull(SUM(Rating) / Count(Rating), 1) FROM    Portal_CustomerReview

      WHERE CustomerId = @CustomerId

      RETURN @value

END

--Call the function

SELECT dbo.Portal_fnGetRestaurantRating(8)