-- Stored Procedure: Generate Monthly Report
CREATE PROCEDURE sp_GenerateMonthlyReport (
    @month INT,
    @year INT,
    @totalRevenue DECIMAL OUT
)
AS
BEGIN
    SELECT @totalRevenue = SUM(amount)
    FROM v_MonthlySales  -- Using a View
    WHERE MONTH(sale_date) = @month
    AND YEAR(sale_date) = @year;
    
    -- Call User-Defined Function
    SELECT dbo.fn_FormatCurrency(@totalRevenue);
END;

-- Function: Format Currency
CREATE FUNCTION fn_FormatCurrency(@amount DECIMAL)
RETURNS VARCHAR(50)
AS
BEGIN
    RETURN '$' + CONVERT(VARCHAR, @amount);
END;

-- View: Monthly Sales Summary
CREATE VIEW v_MonthlySales AS
SELECT 
    YEAR(order_date) AS year,
    MONTH(order_date) AS month,
    SUM(total_amount) AS amount,
    COUNT(*) AS order_count
FROM orders
GROUP BY YEAR(order_date), MONTH(order_date);