SQL：如何计算总计列的行数？

Question

如何计算总计列的行数？

我已经建立了一个查询，将显示每个订单中有多少项目，但我需要做每个总和的计数。我的目标是看有多少人买了3个项目，有多少买了4，等等

SELECT Orders.id, 
    sum(Quantity) AS "Box Count" 
    FROM OrderLines 
    INNER JOIN Orders ON OrderLines.Order_id = Orders.id 
    INNER JOIN Products ON OrderLines.Product_id = Products.id 
    WHERE (Products.ProductType_id = 2) AND Orders.shipdate > '10/01/2014' 
GROUP BY Orders.id 

它返回这样的：

id Box Count 
----- --------- 
68015   6 
69660   3 
70923   3 
72697   13 

我希望它返回此：

Box Count Total Count 
--------- ----------- 
     3   2 
     6   1 
     13   1 

Answer 1

你可以使用第二个查询：

SELECT 
[Box Count] 
,COUNT(*) AS [Total Count] 
FROM 
(
    SELECT 
    Orders.id, 
    sum(Quantity) AS "Box Count" 
    FROM OrderLines 
    INNER JOIN Orders ON OrderLines.Order_id = Orders.id 
    INNER JOIN Products ON OrderLines.Product_id = Products.id 
    WHERE (Products.ProductType_id = 2) AND Orders.shipdate > '10/01/2014' 
    GROUP BY Orders.id 
) AS InnerQuery 
GROUP BY [Box Count] 
ORDER BY COUNT(*) DESC -- optional