sql - Order By Clause 不适用于 GROUP BY

Question

我正在尝试使用以下按小时计算订单数量的函数：

SELECT
    COUNT(id) total,
    DATENAME(HOUR, purchased_on) label,
    site
FROM dhs.dbo.orders
WHERE purchased_on >= '01/16/2013'
GROUP BY DATENAME(HOUR, purchased_on), site
ORDER BY label DESC

即使我正在使用 ORDER BY 子句，我也得到以下结果，该子句应该将它们从最高标签到最低标签排列：

total   label   site
2         9     AMAZON
1         9     DHS
2         8     AMAZON
1         7     AMAZON
1         6     AMAZON
1         4     AMAZON
1         12    AMAZON
3         11    AMAZON
1         10    AMAZON
1         10    DHS  

为什么订单不工作？

Answer 1

DATENAME返回一个VARCHAR。

将其替换为DATEPART：

SELECT  COUNT(id) total,
        DATEPART(HOUR, purchased_on) label,
        site
FROM    dhs.dbo.orders
WHERE   purchased_on >= '01/16/2013'
GROUP BY
        DATEPART(HOUR, purchased_on), site
ORDER BY
        label DESC