Question

我需要对每个person_id列进行排序，其中顺序优先级为：

实际：1> 0
类型：Reg> Zee = Con
date_start：DESC

因此，根据数据：

+----+-----------+------+------------+------------+--------+
| id | person_id | type | date_start | date_end   | actual |
+----+-----------+------+------------+------------+--------+
| 1  | 1         | Reg  | 01-01-2018 | 31-01-2018 | 0      |
+----+-----------+------+------------+------------+--------+
| 2  | 1         | Con  | 01-02-2019 | 01-05-2019 | 0      |
+----+-----------+------+------------+------------+--------+
| 3  | 2         | Reg  | 01-01-2018 | 31-05-2018 | 0      |
+----+-----------+------+------------+------------+--------+
| 4  | 2         | Reg  | 01-05-2018 | 31-07-2019 | 1      |
+----+-----------+------+------------+------------+--------+
| 5  | 2         | Con  | 01-06-2018 | 31-04-2020 | 1      |
+----+-----------+------+------------+------------+--------+
| 6  | 2         | Zee  | 31-05-2019 | 31-08-2019 | 1      |
+----+-----------+------+------------+------------+--------+

我需要查询有关person_id = 1的结果：

    +----+-----------+------+------------+------------+--------+
    | id | person_id | type | date_start | date_end   | actual |
    +----+-----------+------+------------+------------+--------+
    | 1  | 1         | Reg  | 01-01-2018 | 31-01-2018 | 0      |
    +----+-----------+------+------------+------------+--------+
    | 2  | 1         | Con  | 01-02-2019 | 01-05-2019 | 0      |
    +----+-----------+------+------------+------------+--------+

对于person_id = 2，结果为：

+----+-----------+------+------------+------------+--------+
| id | person_id | type | date_start | date_end   | actual |
+----+-----------+------+------------+------------+--------+
| 4  | 2         | Reg  | 01-05-2018 | 31-07-2019 | 1      |
+----+-----------+------+------------+------------+--------+
| 6  | 2         | Zee  | 31-05-2019 | 31-08-2019 | 1      |
+----+-----------+------+------------+------------+--------+
| 5  | 2         | Con  | 01-06-2018 | 31-04-2020 | 1      |
+----+-----------+------+------------+------------+--------+
| 3  | 2         | Reg  | 01-01-2018 | 31-05-2018 | 0      |
+----+-----------+------+------------+------------+--------+

（此外，这是一个附加的问题，我需要从查询中获取最旧的start_date，但仅在各行之间保持日期连续性的情况下）

Answer 1

您可以使用CASE表达式添加特定的权重：

ORDER BY actual DESC, CASE WHEN `type` = 'Reg' THEN 1 ELSE 2 END, date_start DESC

如何按字符串类型而不是字母的列进行排序？

1 个答案: