在SQL Server 2005中使用AVG聚合函數

Question

我有一個“訂單”表：

ID  CustomerID  Freight
1      VINET      32.38
2      TOMPS      11.61
.        .          .
.        .          . 
.        .          .

我只想選擇運費超過平均水平的那些customerID ！！

SELECT CustomerID FROM Orders WHERE CustomerID IN(SELECT CustomerID,AVG(Freight) AVGFreight FROM Orders Group By CustomerID )

我知道到這里為止，但是我該如何比較運費和平均運費呢？ 請幫我謝謝

Answer 1

我假設一個客戶每個都有1條記錄。

從dbo.Orders中選擇客戶ID運費> =（從dbo.Orders中選擇@AvgFreight = AVG（Freight））

我不確定這是否行得通。 試試吧。
支持@marc_s的答案，因為我以他的答復為依據。

SELECT CustomerID
FROM dbo.Orders 
WHERE AVG(Freight) >= (SELECT AVG(Freight) FROM dbo.Orders)
GROUP BY CustomerID

Answer 2

這個怎么樣：

SELECT CustomerID 
FROM dbo.Orders 
WHERE Freight >= (SELECT AVG(Freight) FROM dbo.Orders)
GROUP BY CustomerID

您選擇了所有客戶，這些客戶的運費均大於表中所有運費的平均值。

Answer 3

CREATE TABLE Orders(
    ID int,
    CustomerId varchar(10),
    Freight money
);
INSERT INTO Orders Values(1,'VINET',10);
INSERT INTO Orders values(2,'VINET',10);
INSERT INTO Orders values(3,'TOMPS',12);
INSERT INTO Orders values(4,'TOMPS',11);

顯示平均值：

Select CustomerId,avg(Freight)AvgFreight
from Orders
group by customerId

| CustomerId | AvgFreight | |------------+------------| | TOMPS | 11.50 | | VINET | 10.00 | |------------+------------|

將運費與平均值進行比較：

Select Orders.CustomerId 
from Orders,
(Select CustomerId,avg(Freight)AvgFreight
from Orders
Group by customerId)t
Where Orders.Freight > t.AvgFreight
And Orders.CustomerId = t.Customerid

| CustomerId | |------------| | TOMPS | |------------|

Answer 4

使用HAVING子句。

SELECT CustomerID
FROM Orders 
GROUP BY CustomerID 
HAVING AVG(Freight) > (SELECT AVG(Freight) FROM Orders)