SQL ORDER BY - 爲什麼它不在這裏工作？

Question

這是表我：

+---------------------+--------+----------+ 
| date    | sku | quantity | 
+---------------------+--------+----------+ 
| 2017-08-23 14:58:00 | 123333 |  2 | 
| 2017-08-23 14:58:00 | 123333 |  1 | 
| 2017-08-23 14:58:00 | 123333 |  1 | 
| 2017-08-23 14:58:00 | 123337 |  2 | 
| 2017-08-23 14:58:00 | 123335 |  1 | 
| 2017-08-23 14:58:00 | 123331 |  1 | 
| 2017-08-23 14:58:00 | 123332 |  2 | 
| 2017-08-23 14:58:00 | 123333 |  1 | 
| 2017-08-23 14:58:00 | 123334 |  1 | 
| 2017-08-23 14:58:00 | 123334 |  3 | 
+---------------------+--------+----------+ 

我想如下執行select語句：

select sku,sum(quantity) as 'total quant' from transactions 
where DATE(date) between '2017-07-23' and '2017-09-23' 
group by sku 
order by quantity desc; 

但我得到這個：

+--------+-------------+ 
| sku | total quant | 
+--------+-------------+ 
| 123332 | 2   | 
| 123337 | 2   | 
| 123333 | 5   | 
| 123334 | 4   | 
| 123335 | 1   | 
| 123331 | 1   | 
+--------+-------------+ 

哪一項不是按我期待的順序排列。 爲什麼訂單不在這裏工作？

邊注我quantity列的數據類型爲int的，我已經試過鑄造在this post但無濟於事建議。

Answer 1

您正在按數量訂購。因爲它沒有被聚合，所以你從每個組中獲得一個任意值。您需要按總數訂購。一種方法是：

order by sum(quantity) desc 

不過，我會建議分配合理的別名（一個不需要進行轉義），並使用：

select sku,sum(quantity) as total_quantity 
from transactions 
where DATE(date) between '2017-07-23' and '2017-09-23' 
group by sku 
order by total_quantity desc; 

Answer 2

您需要通過SUM(quantity)來訂購。

SELECT sku, SUM(quantity) AS 'total quant' 
FROM transactions 
WHERE DATE(date) BETWEEN '2017-07-23' AND '2017-09-23' 
GROUP BY sku 
ORDER BY SUM(quantity) DESC; 

Answer 3

你應該使用：

order by sum(quantity)