CREATE FUNCTION dbo.GetProductCount ()
RETURNS INT
AS
BEGIN
    DECLARE @Count INT = 0;
    SELECT @Count=COUNT(1)
         FROM Production.Product
    RETURN @Count;
END
GO
-- EXECUTION
SELECT dbo.GetProductCount()

-- Parameterized Scalar Function
CREATE FUNCTION dbo.Divide (@A INT, @B INT)
RETURNS INT
AS
BEGIN
   RETURN @A / @B
End
GO
-- EXECUTION
SELECT dbo.Divide (4,2)