PostgreSQL：有序结果 [英] postgresql: ordered result
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问题描述
我有一个表格，如下所示：
I've a table that looks like:
id | user_id | activity_id | activity_type | root_id | is_root | timestamp
----+---------+-------------+---------------+---------+---------+-----------
1 | 1 | 1 | text | 1 | 1 | 5
2 | 2 | 2 | text | 1 | 0 | 6
3 | 3 | 3 | text | 1 | 0 | 10
4 | 2 | 10 | text | 10 | 1 | 50
5 | 1 | 11 | text | 10 | 0 | 90
6 | 3 | 12 | text | 10 | 0 | 100
7 | 3 | 20 | text | 20 | 1 | 190
8 | 2 | 21 | text | 20 | 0 | 130
9 | 3 | 22 | text | 20 | 0 | 150
10 | 3 | 22 | text | 20 | 0 | 150
11 | 3 | 22 | text | 20 | 0 | 150
我想要一个像这样的输出
I want an out put like
id | user_id | activity_id | activity_type | root_id | is_root | timestamp
----+---------+-------------+---------------+---------+---------+-----------
7 | 3 | 20 | text | 20 | 1 | 120
8 | 2 | 21 | text | 20 | 0 | 130
11 | 3 | 22 | text | 20 | 0 | 150
9 | 3 | 22 | text | 20 | 0 | 150
10 | 3 | 22 | text | 20 | 0 | 150
4 | 2 | 10 | text | 10 | 1 | 50
5 | 1 | 11 | text | 10 | 0 | 90
6 | 3 | 12 | text | 10 | 0 | 100
1 | 1 | 1 | text | 1 | 1 | 5
2 | 2 | 2 | text | 1 | 0 | 6
3 | 3 | 3 | text | 1 | 0 | 10
root_id应该放在一个组中，并且该组的第一行应该有is_root = 1.应根据根DESC的时间戳对组进行排序，但应将根的子级按ASC排序（基于时间戳）
The root_id should be placed in one group, and the first row of that group should have is_root = 1. The groups should be sorted on the basis of timestamp of root DESC, but the children of the root should be sorted ASC (timestamp based)
该问题的相关列是root_id，is_root，时间戳。
感谢您的帮助。
谢谢
推荐答案
您在说这个吗？
ORDER BY root_id DESC, is_root DESC, timestamp
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