SELECT语句不返回结果

你不需要分组依据ProductID和Orderqty.如果您对它们进行灌浆,则会将其分组到单个订单商品级别.所以你永远不会超过300

订单上的商品数量应该是真的总和Orderqty.

尝试:

SELECT scpii.LastName + ', ' + scpii.FirstName AS 'Customer Name', 
       ssoh.Status AS 'Order Status', 
       ssoh.OrderDate AS 'Date Ordered', 
       SUM (ssod.OrderQty) AS 'Count of Items', 
       AVG (ssod.OrderQty) AS 'Average Quantity'
FROM Sales.CustomerPII scpii
INNER JOIN Sales.SalesOrderHeader ssoh
  ON ssoh.CustomerID = scpii.CustomerID
INNER JOIN Sales.SalesOrderDetail ssod
  ON ssod.SalesOrderID = ssoh.SalesOrderID
GROUP BY scpii.LastName, 
         scpii.FirstName, 
         ssoh.Status, 
         ssoh.OrderDate 
HAVING SUM (ssod.OrderQty) > 300;