Listing 1: Code That Creates and Populates the EmpOrders Table
USE tempdb
GO
IF OBJECT_ID('EmpOrders') IS NOT NULL
  DROP TABLE EmpOrders
GO

CREATE TABLE EmpOrders
(
  empid      int      NOT NULL,
  ordermonth datetime NOT NULL,
  qty        int      NOT NULL,
  PRIMARY KEY(empid, ordermonth, qty)
)

INSERT INTO EmpOrders(empid, ordermonth, qty)
  SELECT O.EmployeeID,
    CAST(CONVERT(char(6), O.OrderDate, 112) + '01' AS datetime) AS ordermonth,
    SUM(Quantity) AS qty
  FROM Northwind.dbo.Orders AS O
    JOIN Northwind.dbo.[Order Details] AS OD
      ON O.OrderID = OD.OrderID
  GROUP BY EmployeeID,
    CAST(CONVERT(char (6), O.OrderDate, 112) + '01' AS datetime)