mysql - 高级 MySQL : Find correlations between poll responses

Question

我有四个 MySQL 表:

用户 (id, name)
民意调查(id、文本)
选项(id、poll_id、文本)
响应(id、poll_id、option_id、user_id)

给定一个特定的民意调查和一个特定的选项，我想生成一个表格，显示其他民意调查中的哪些选项最相关。

假设这是我们的数据集:

TABLE users:
+------+-------+
| id   | name  |
+------+-------+
|    1 | Abe   |
|    2 | Bob   |
|    3 | Che   |
|    4 | Den   |
+------+-------+

TABLE polls:
+------+-----------------------+
| id   | text                  |
+------+-----------------------+
|    1 | Do you like apples?   |
|    2 | What is your gender?  |
|    3 | What is your height?  |
|    4 | Do you like polls?    |
+------+-----------------------+

TABLE options:

+------+----------+---------+
| id   | poll_id  | text    |
+------+----------+---------+
|    1 | 1        | Yes     |
|    2 | 1        | No      |
|    3 | 2        | Male    |
|    4 | 2        | Female  |
|    5 | 3        | Short   |
|    6 | 3        | Tall    |
|    7 | 4        | Yes     |
|    8 | 4        | No      |
+------+----------+---------+

TABLE responses:

+------+----------+------------+----------+
| id   | poll_id  | option_id  | user_id  |
+------+----------+------------+----------+
|    1 | 1        | 1          | 1        |
|    2 | 1        | 2          | 2        |
|    3 | 1        | 2          | 3        |
|    4 | 1        | 2          | 4        |
|    5 | 2        | 3          | 1        |
|    6 | 2        | 3          | 2        |
|    7 | 2        | 3          | 3        |
|    8 | 2        | 4          | 4        |
|    9 | 3        | 5          | 1        |
|   10 | 3        | 6          | 2        |
|   10 | 3        | 5          | 3        |
|   10 | 3        | 6          | 4        |
|   10 | 4        | 7          | 1        |
|   10 | 4        | 7          | 2        |
|   10 | 4        | 7          | 3        |
|   10 | 4        | 7          | 4        |
+------+----------+------------+----------+

给定轮询 ID 1 和选项 ID 2，生成的表应该是这样的:

+----------+------------+-----------------------+
| poll_id  | option_id  | percent_correlated    |
+----------+------------+-----------------------+
| 4        | 7          | 100                   |
| 2        | 3          | 66.66                 |
| 3        | 6          | 66.66                 |
| 2        | 4          | 33.33                 |
| 3        | 5          | 33.33                 |
| 4        | 8          | 0                     |
+----------+------------+-----------------------+

基本上，我们确定了所有响应民意调查 ID 1 并选择了选项 ID 2 的用户，并且我们正在查看所有其他民意调查以了解他们中有多少百分比也选择了其他选项。

Answer 1

没有方便的实例来测试，你能看看这是否得到正确的结果:

select
        poll_id,
        option_id,
        ((psum - (sum1 * sum2 / n)) / sqrt((sum1sq - pow(sum1, 2.0) / n) * (sum2sq - pow(sum2, 2.0) / n))) AS r,
        n
from
(
    select 
        poll_id,
        option_id,
        SUM(score) AS sum1,
        SUM(score_rev) AS sum2,
        SUM(score * score) AS sum1sq,
        SUM(score_rev * score_rev) AS sum2sq,
        SUM(score * score_rev) AS psum,
        COUNT(*) AS n
    from
    (
            select 
                responses.poll_id, 
                responses.option_id,
                CASE 
                    WHEN user_resp.user_id IS NULL THEN SELECT 0
                    ELSE SELECT 1
                END CASE as score,
                CASE 
                    WHEN user_resp.user_id IS NULL THEN SELECT 1
                    ELSE SELECT 0
                END CASE as score_rev,
            from responses left outer join 
                    (
                        select 
                            user_id
                        from 
                            responses 
                        where
                            poll_id = 1 and 
                            option_id = 2
                    )user_resp  
                        ON (user_resp.user_id = responses.user_id)
    ) temp1 
    group by
        poll_id,
        option_id
)components