mysql - MySQL Query 在同一张表上的查询中

Question

我有一张像这样的桌子：

Status | Quantity | PeriodDate
------------------------------
100    | 2        | 2013-07-02
100    | 3        | 2013-07-02
100    | 5        | 2013-07-02
100    | 3        | 2013-07-03
100    | 1        | 2013-07-03
100    | 0        | 2013-07-04
100    | 0        | 2013-07-04
100    | 5        | 2013-07-04
100    | 6        | 2013-07-05
100    | 4        | 2013-07-06
100    | 8        | 2013-07-06

而且我需要选择数据，以便它显示一个范围内每个不同日期的数量计数。我原以为我可以做一些事情：

SELECT DISTINCT PeriodDate, SUM(Quantity) as TotalQuantity where PeriodDate BETWEEN '2013-07-02' AND '2013-07-04'

但这会返回一行，其中包含所有数量的全部总和。

我追求的是：

TotalQuantity | PeriodDate
--------------------------
10            | 2013-07-02
4             | 2013-07-03
5             | 2013-07-04
6             | 2013-07-05

我如何实现这一目标？

Answer 1

SELECT PeriodDate, 
       SUM(Quantity) as TotalQuantity 
from your_table
where PeriodDate BETWEEN '2013-07-02' AND '2013-07-05'
group by PeriodDate 

Answer 2

Distinct 适用于PeriodDate和TotalQuantity。DISTINCT您需要使用 ，而不是使用GROUP BY。

SELECT PeriodDate, SUM(Quantity) as TotalQuantity 
FROM ???
WHERE PeriodDate BETWEEN '2013-07-02' AND '2013-07-04'
GROUP BY PeriodDate

说明： Distinct 用于消除结果集中的重复行。

进一步解释：http ://www.mysqltutorial.org/mysql-distinct.aspx