How to write an SQL query generating a history of the sums of a column at different timestamps?-CodePudding

In a table, I have events showing values (x) for things with different IDs at different event timestamps.

WITH
  events AS (
  SELECT 1 AS thing_id, 1 AS x, TIMESTAMP('2021-12-01 00:00:00') AS event_timestamp
  UNION ALL
  SELECT 1, 3, TIMESTAMP('2021-12-01 00:01:00')
  UNION ALL
  SELECT 2, 5, TIMESTAMP('2021-12-01 00:02:00')
  UNION ALL
  SELECT 1, 0, TIMESTAMP('2021-12-01 00:03:00'))
SELECT
  * FROM events

 ---------- --- --------------------- 
| thing_id | x |   event_timestamp   |
 ---------- --- --------------------- 
|        1 | 1 | 2021-12-01 00:00:00 |
|        1 | 3 | 2021-12-01 00:01:00 |
|        2 | 5 | 2021-12-01 00:02:00 |
|        1 | 0 | 2021-12-01 00:03:00 |
 ---------- --- ---------------------

I'd like to obtain a history showing the sum of all current x values for each known event_timestamp.

 --------------------- ------- 
|   event_timestamp   | x_sum |
 --------------------- ------- 
| 2021-12-01 00:00:00 | 1     |
| 2021-12-01 00:01:00 | 3     |
| 2021-12-01 00:02:00 | 8     |
| 2021-12-01 00:03:00 | 5     |
 --------------------- -------

What would the needed SQL statement look like? I'm trying to think about grouping per thing_id, windowing, and maybe cross joining on all event_timestamps, but I can't figure it out.

CodePudding user response：

Having found explanations of the