Split postgres records into groups based on time fields - postgresql

Question

I have a table with records that look like this:
| id | coord-x | coord-y | time |
---------------------------------
| 1 | 0 | 0 | 123 |
| 1 | 0 | 1 | 124 |
| 1 | 0 | 3 | 125 |
The time column represents a time in milliseconds. What I want to do is find all coord-x, coord-y as a set of points for a given timeframe for a given id. For any given id there is a unique coord-x, coord-y, and time.
What I need to do however is group these points as long as they're n milliseconds apart. So if I have this:
| id | coord-x | coord-y | time |
---------------------------------
| 1 | 0 | 0 | 123 |
| 1 | 0 | 1 | 124 |
| 1 | 0 | 3 | 125 |
| 1 | 0 | 6 | 140 |
| 1 | 0 | 7 | 141 |
I would want a result similar to this:
| id | points | start-time | end-time |
| 1 | (0,0), (0,1), (0,3) | 123 | 125 |
| 1 | (0,140), (0,141) | 140 | 141 |
I do have PostGIS installed on my database, the times I posted above are not representative but I kept them small just as a sample, the time is just a millisecond timestamp.

Answer 1

The tricky part is picking the expression inside your GROUP BY. If n = 5, you can do something like time / 5. To match the example exactly, the query below uses (time - 3) / 5. Once you group it, you can aggregate them into an array with array_agg.
SELECT
array_agg(("coord-x", "coord-y")) as points,
min(time) AS time_start,
max(time) AS time_end
FROM "<your_table>"
WHERE id = 1
GROUP BY (time - 3) / 5
Here is the output
+---------------------------+--------------+------------+
| points | time_start | time_end |
|---------------------------+--------------+------------|
| {"(0,0)","(0,1)","(0,3)"} | 123 | 125 |
| {"(0,6)","(0,7)"} | 140 | 141 |
+---------------------------+--------------+------------+