Listing 1: Stored Procedure That Uses the UNION Operator to Return Lease-Detail 
Information
CREATE PROC GetInvoiceDetails @leasenumber int
AS
-- Get leased furniture.
SELECT l.leasenumber, l.Term,  'Furniture' AS ITEM, lf.furnitureid AS ITEMID,
lf.quantity, f.LeaseRate, lf.quantity * f.leaserate AS LineItemTotal,
NULL AS InvoiceTotal
FROM Leases AS l
INNER JOIN leases_furniture AS lf ON l.leasenumber = lf.leasenumber
AND l.leasenumber = @leasenumber
INNER JOIN furniture AS f ON lf.furnitureid = f.furnitureid
UNION
-- Get leased trucks.
SELECT l.leasenumber, l.Term, 'Truck' AS ITEM, lv.TruckID AS ITEMID,
lv.quantity, v.LeaseRate, lv.quantity * v.LeaseRate AS LineItemTotal,
NULL AS InvoiceTotal
FROM leases AS l
INNER JOIN leases_Trucks AS lv ON l.leasenumber = lv.leasenumber
AND l.leasenumber = @leasenumber
INNER JOIN Trucks AS v ON lv.TruckID = v.TruckID
UNION
-- Get leased computers.
SELECT l.leasenumber, l.Term,  'Computer' AS ITEM, lc.computerid AS ITEMID,
lc.quantity, c.LeaseRate, lc.quantity * c.LeaseRate AS LineItemTotal,
NULL AS InvoiceTotal
FROM leases AS l
INNER JOIN leases_computers AS lc ON l.leasenumber = lc.leasenumber
AND l.leasenumber = @leasenumber
INNER JOIN computers AS c ON lc.computerid = c.computerid
-- Get invoice grand total.
UNION
SELECT NULL, NULL, NULL, NULL, NULL, NULL, NULL, SUM (LineItemTotal) FROM
(SELECT SUM(lf.quantity * f.leaserate) AS LineItemTotal
FROM leases_furniture AS lf
INNER JOIN furniture AS f ON lf.furnitureid = f.furnitureid
AND lf.leasenumber = @leasenumber
UNION
SELECT SUM(lv.quantity * v.leaserate) AS LineItemTotal
FROM leases_Trucks AS lv
INNER JOIN Trucks AS v ON lv.TruckID = v.TruckID
AND lv.leasenumber = @leasenumber
UNION
SELECT SUM(lc.quantity * c.leaserate) AS LineItemTotal
FROM leases_computers AS lc
INNER JOIN computers AS c ON lc.computerid = c.computerid
AND lc.leasenumber = @leasenumber
) AS T
-- Order the results.
ORDER BY l.leasenumber DESC, item ASC