T-SQL SUM Total

Question

Below I have a T-SQL query that brings back amount of purchased items, less discounts and the total - grouped by month/year of purchase. How can I update the Query to return a Grand Total Row where I would can add up the amounts in the Total Column? It would be good to be able to add up all the rows but my main item is I need to be able to get a grand total. Thanks.

    Select DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4)) 
    AS [Month],
    SUM(Amount) AS [Amount],
    SUM(Discount1) AS [Discount 1],
    SUM(Discount2) AS [Discount 2],
    SUM(Amount - Discount1 - Discount2) AS [Total]
    From 
    Orders
    JOIN Customer on orders.cust_ky=customer.cust_ky
    GROUP BY DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4))
    ORDER BY MAX(OrderDate)

Answer 1

Depending on your version of sql-server, you might be able to implement the rollup function (SQL-Server 2005+):

Select DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4)) AS [Month],
    SUM(Amount) AS [Amount],
    SUM(Discount1) AS [Discount 1],
    SUM(Discount2) AS [Discount 2],
    SUM(Amount - Discount1 - Discount2) AS [Total]
From Orders
JOIN Customer 
    on orders.cust_ky=customer.cust_ky
GROUP BY ROLLUP(DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4)))
ORDER BY MAX(OrderDate)

Or you can use a UNION ALL similar to this, where the second query gets the total without the GROUP BY:

Select DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4)) AS [Month],
    SUM(Amount) AS [Amount],
    SUM(Discount1) AS [Discount 1],
    SUM(Discount2) AS [Discount 2],
    SUM(Amount - Discount1 - Discount2) AS [Total]
From Orders
JOIN Customer 
    on orders.cust_ky=customer.cust_ky
GROUP BY DATENAME(month, [OrderDate]) + ' ' + CAST(YEAR(OrderDate) AS CHAR(4))
union all
Select 'Total',
    SUM(Amount) AS [Amount],
    SUM(Discount1) AS [Discount 1],
    SUM(Discount2) AS [Discount 2],
    SUM(Amount - Discount1 - Discount2) AS [Total]
From Orders
JOIN Customer 
    on orders.cust_ky=customer.cust_ky