Mysql 求滑动订单问题-CFANZ编程社区

Mysql 求滑动订单问题

1.需求

求出滑动订单

2.示例

这里的滑动订单指的是，按照每12个月或者每个季度【3个月】求出订单的某个特征数。下面给出一个示例。

有表orders。表数据如下：

mysql> select * from orders;
+-------------+-----------+
| order_month | order_num |
+-------------+-----------+
| 2017-02-01  |        23 |
| 2017-03-01  |        26 |
| 2017-04-01  |        24 |
| 2017-05-01  |        27 |
| 2017-06-01  |        26 |
| 2017-07-01  |        32 |
| 2017-08-01  |        34 |
| 2017-09-01  |        30 |
| 2017-10-01  |        31 |
| 2017-11-01  |        32 |
| 2017-12-01  |        33 |
| 2018-01-01  |        31 |
| 2018-02-01  |        34 |
| 2018-03-01  |        34 |
| 2018-04-01  |        38 |
| 2018-05-01  |        39 |
| 2018-06-01  |        35 |
| 2018-07-01  |        49 |
| 2018-08-01  |        56 |
| 2018-09-01  |        55 |
+-------------+-----------+
20 rows in set (0.00 sec)

那么滑动订单问题就是指求出表中起始月份+12月的总订单数。

+-------------+------------+
| start_month | end_month  |
+-------------+------------+
| 2017-02-01  | 2018-02-01 |
| 2017-03-01  | 2018-03-01 |
| 2017-04-01  | 2018-04-01 |
| 2017-05-01  | 2018-05-01 |
| 2017-06-01  | 2018-06-01 |
| 2017-07-01  | 2018-07-01 |
| 2017-08-01  | 2018-08-01 |
| 2017-09-01  | 2018-09-01 |
+-------------+------------+
8 rows in set (0.00 sec)

如上图所示就是分别求出 2017-02-01 => 2018-02-01的总订单数；…2017-09-01 => 2018-09-01的总订单数。最后的结果如下所示：

+-------------+------------+-------+
| start_month | end_month  | total |
+-------------+------------+-------+
| 2017-02-01  | 2018-02-01 |   383 |
| 2017-03-01  | 2018-03-01 |   394 |
| 2017-04-01  | 2018-04-01 |   406 |
| 2017-05-01  | 2018-05-01 |   421 |
| 2017-06-01  | 2018-06-01 |   429 |
| 2017-07-01  | 2018-07-01 |   452 |
| 2017-08-01  | 2018-08-01 |   476 |
| 2017-09-01  | 2018-09-01 |   497 |
+-------------+------------+-------+
8 rows in set (0.00 sec)

3.代码一

select
 t1.start_month
,t1.end_month
,sum(order_num) as total
from orders ord1
inner join 
(
  select 
  order_month as start_month
  ,date_add(order_month,interval 12 month) as end_month
  from orders ord1
  where date_add(ord1.order_month,interval 12 month) <= (select max(order_month) as max_month from orders)
)as t1
on ord1.order_month between t1.start_month and t1.end_month
group by t1.start_month;

这里有一点需要注意：在inner join...on 的语句中，on中的条件不一定非要是=号，可以使用>,<,!=,between on等等.

3.代码二

select 
  date_format(a.order_month,'%Y%m') as start_month
  ,date_format(b.order_month,'%Y%m') as end_month
  ,sum(c.order_num) as total
from orders a
inner join orders b
  on date_add(a.order_month,interval 12 month ) = b.order_month
inner join orders c
  on c.order_month between a.order_month and b.order_month
group by a.order_month,b.order_month;

这个代码和上述的代码效果一样。