SQL查询（如果可能）

Question

我有一张桌子

+------------------------+
| DATE       | INT       |  
+------------------------+
| [DATE]     | [TICKETS] |  
| ---------- | ----------|  
| 01/01/2016 | 100       |  
| 01/02/2016 | 10        |  
| 01/03/2016 | 30        |  
| 02/15/2016 | 28        |  
| 02/29/2016 | 80        |  
| 01/01/2017 | 25        |  
| 01/02/2017 | 120       |  
| 01/03/2017 | 60        |  
| 02/15/2017 | 72        |  
| 02/28/2017 | 12        |  
 ------------------------

我希望（SELECT）查询（如果可能）具有类似

---------------------------------------------
                    | [DATE]     | [TICKETS2016]  | [TICKETS2017] |  
                   _| ---------- | -------------- | ------------- |  
highest           / | 01/01/2017 | 100            |  25           | 
year for the     /  | 01/02/2017 | 10             |  120          | 
common days.     \  | 01/03/2017 | 30             |  60           | 
                  \_| 02/15/2017 | 28             |  72           | 
Exists only at 2017>| 02/28/2017 | NULL           |  12           | 
Exists only at 2016>| 02/29/2016 | 80             |  NULL         | 
                     ---------------------------------------------

由于我是SQL的新手，因此我想寻求您的帮助。

非常感谢您的宝贵时间。

Answer 1

您可以使用条件聚合来做到这一点：

select format(date, '%m-%d') as mmdd,
       sum(case when year(date) = 2016 then tickets end) as tickets_2016,
       sum(case when year(date) = 2017 then tickets end) as tickets_2017
from t
group by format(date, '%m-%d');

Answer 2

最后，这就是我想要的。 感谢所有人的帮助。

select date(max(date)) as mmdd,
       sum(case when year(date) = 2016 then tickets end) as tickets_2016,
       sum(case when year(date) = 2017 then tickets end) as tickets_2017
from t
group by date_format(date, '%m-%d');