是否可以从 Timescale 中的双时态 table 访问审计数据

Question

在 Why Use TimescaleDB over Relational DBs? 文章中，针对双时态用例给出了以下示例

SELECT
    time_bucket('1 day', time) AS day,
    asset_code,
    last(price, time_recorded)
FROM prices
WHERE time > '2017-01-01'
GROUP BY day, asset_code
ORDER BY day DESC, asset_code;

如果我们假设 prices table 包含一个 recorded_by 列，是否可以编写一个 returns 同时包含 time_recorded 和 recorded_by列?

例如给定以下输入：

+------------------+------------+-------+------------------+-------------+
|       time       | asset_code | price |  time_recorded   | recorded_by |
+------------------+------------+-------+------------------+-------------+
| 2019-08-08 12:00 |          1 | 9     | 2019-08-08 12:00 | foo         |
| 2019-08-09 15:30 |          1 | 10    | 2019-08-09 15:30 | foo         |
| 2019-08-08 12:00 |          1 | 9.5   | 2019-08-09 15:00 | bar         |
+------------------+------------+-------+------------------+-------------+

您会得到以下输出：

+------------+------------+-------+------------------+-------------+
|    day     | asset_code | price |  time_recorded   | recorded_by |
+------------+------------+-------+------------------+-------------+
| 2019-08-09 |          1 | 10    | 2019-08-09 15:30 | foo         |
| 2019-08-08 |          1 | 9.5   | 2019-08-09 13:00 | bar         |
+------------+------------+-------+------------------+-------------+

Answer 1

事实证明，您实际上可以让最后一个函数的两个参数引用同一列，例如

SELECT
    time_bucket('1 day', time) AS day,
    asset_code,
    last(price, time_recorded) AS price,
    last(time_recorded, time_recorded) AS time_recorded,
    last(recorded_by, time_recorded) AS recorded_by
FROM prices
WHERE time > '2017-01-01'
GROUP BY day, asset_code
ORDER BY day DESC, asset_code;

是否可以从 Timescale 中的双时态 table 访问审计数据

Is it possible to access audit data from a bi-temporal table in Timescale

timescaledb