Question

我需要列出每个客户的得分在一段时间内的分布情况。

我的问题是我每个月都没有得分。因此，我需要将前一个条目计为本月的分数。

最重要的是，如果在同一个月内注册了两个分数，则该月内只有最新分数计算

我的数据表看起来像这样：

| id | customer_id | score | created_at |   
| 1  |     1       |  4    | 2016-05-01 |   
| 2  |     2       |  4    | 2016-05-01 |  
| 3  |     3       |  4    | 2016-05-01 |   
| 4  |     1       |  3    | 2016-05-15 |  
| 5  |     2       |  2    | 2016-06-01 |   
| 6  |     3       |  2    | 2016-06-13 |   
| 7  |     2       |  4    | 2016-07-01 |  
| 8  |     2       |  2    | 2016-08-21 |  
| 9  |     1       |  2    | 2016-08-01 |  
| 10 |     1       |  1    | 2016-08-31 |

我想得到这样的结果：

|customer_id |   MONTH     | Score |
|     1      |   2016-05   |   3   |
|     2      |   2016-05   |   4   |
|     3      |   2016-05   |   4   |
|     1      |   2016-06   |   3   |
|     2      |   2016-06   |   2   |
|     3      |   2016-06   |   2   |
|     1      |   2016-07   |   3   |
|     2      |   2016-07   |   4   |
|     3      |   2016-07   |   2   |
|     1      |   2016-08   |   1   |
|     2      |   2016-08   |   2   |
|     3      |   2016-08   |   2   |
|     1      |   2016-09   |   1   |
|     2      |   2016-09   |   2   |
|     3      |   2016-09   |   2   |

Answer 1

您可以使用以下QUERY：

SELECT tt.customer_id,CONCAT(YEAR(tt.created_at),'-',MONTH(tt.created_at)) AS MONTH,tt.score 
FROM myTable tt INNER JOIN (SELECT MAX(id) AS max_id,customer_id,YEAR(created_at) AS selYear,
MONTH(created_at) AS selMonth FROM myTable GROUP BY customer_id,YEAR(created_at),MONTH(created_at)) sel_tt
ON tt.id=sel_tt.max_id AND tt.customer_id=sel_tt.customer_id AND YEAR(tt.created_at)=sel_tt.selYear 
AND MONTH(tt.created_at)=sel_tt.selMonth ORDER BY tt.customer_id,tt.created_at

MySQL：每月计数一次，直到输入更改为止

1 个答案: