SQL 滞后 window 和自定义逻辑

Question

我正在处理这个数据集 https://dbfiddle.uk/?rdbms=sqlserver_2014&fiddle=447a5d2c33b04346e70dab0a8d098655

自定义逻辑：按名称、考试中心、课程名称、考试类型分组。如果进行了重新测试，则比较分数 - 如果较高者优先于最高分数或原始分数。

延迟：根据以上选择的行，如果在 4 天内剩余记录集示例之间存在滞后 window，则应选择最高分记录。

如有任何建议，我们将不胜感激。

示例数据

+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+-----------------------------------------------+
| recordid | Name  | testcentre | coursename | testtype | testscore |  testdate  | retestflag | Preferred_Output |                 RejectReason                  |
+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+-----------------------------------------------+
|        1 | Sam   | Paris      | English    | IELTS    |        90 | 01/02/2019 |          0 |                0 |                                               |
|        3 | Sam   | Paris      | English    | IELTS    |        95 | 02/02/2019 |          1 |                1 | Better score in retest                        |
|        4 | Sam   | Paris      | English    | TOEFL    |        80 | 04/02/2019 |          0 |                0 | Within 4 days of previous test                |
|       21 | Sam   | Paris      | English    | IELTS    |        95 | 02/02/2018 |          1 |                1 | marked as retest without base.needs inclusion |
|        5 | Jack  | London     | English    | IELTS    |        90 | 01/02/2019 |          0 |                1 | Same or bad score in retest                   |
|        8 | Jack  | London     | English    | IELTS    |        90 | 02/02/2019 |          1 |                0 | Same or bad score in retest                   |
|        7 | Louis | Brazil     | English    | IELTS    |        70 | 01/02/2019 |          0 |                1 | Same score in retest                          |
|       11 | Louis | Brazil     | English    | IELTS    |        70 | 02/02/2019 |          1 |                0 | Same score in retest                          |
|       13 | Louis | Brazil     | English    | TOEFL    |       100 | 04/02/2019 |          0 |                0 | Within 4 days of previous test                |
|       55 | Sam   | Paris      | English    | IELTS    |        90 | 01/02/2016 |          0 |                1 | Older test, no follow on                      |
|       60 | Sam   | Paris      | English    | IELTS    |        95 | 01/08/2019 |          0 |                1 | same score in retest                          |
|       61 | Sam   | Paris      | English    | IELTS    |        95 | 02/08/2019 |          1 |                0 |                                               |
|       62 | Sam   | Paris      | English    | TOEFL    |        80 | 04/01/2020 |          0 |                1 | More than 4 days, included                    |
+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+-----------------------------------------------+

期望的输出

+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+
| recordid | Name  | testcentre | coursename | testtype | testscore |  testdate  | retestflag | Preferred_Output |
+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+
|        3 | Sam   | Paris      | English    | IELTS    |        95 | 02/02/2019 |          1 |                1 |
|       21 | Sam   | Paris      | English    | IELTS    |        95 | 02/02/2018 |          1 |                1 |
|        5 | Jack  | London     | English    | IELTS    |        90 | 01/02/2019 |          0 |                1 |
|        7 | Louis | Brazil     | English    | IELTS    |        70 | 01/02/2019 |          0 |                1 |
|       55 | Sam   | Paris      | English    | IELTS    |        90 | 01/02/2016 |          0 |                1 |
|       60 | Sam   | Paris      | English    | IELTS    |        95 | 01/08/2019 |          0 |                1 |
|       62 | Sam   | Paris      | English    | TOEFL    |        80 | 04/01/2020 |          0 |                1 |
+----------+-------+------------+------------+----------+-----------+------------+------------+------------------+

Answer 1

select * from (
  select *, row_number() over (partition by name order by testscore desc) rn
  from test
) t
where rn = 1

Fiddle

Answer 2

根据您的示例数据和描述，这似乎符合您的要求：

select t.*
from (select t.*,
             row_number() over (partition by name, testcentre, coursename, testtype order by testscore desc) as seqnum,
             count(*) over (partition by name, testcentre, coursename, testtype) as cnt
      from test t
     ) t
where seqnum = 1 and cnt >= 2;

这不包括“4 天内”的条件，因为该条件没有明确解释。例如，如果有一系列 5 次测试，每次间隔 3 天，会发生什么情况？

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