Count blocks of data based on id and status code - sql

Question

I have a dataset that looks something like this
id
status
datetime
123456
0
07/02/2023 12:43
123456
4
07/02/2023 12:49
123456
5
07/02/2023 12:58
123456
5
07/02/2023 13:48
123456
7
07/02/2023 14:29
123456
0
07/02/2023 14:50
123456
4
07/02/2023 14:50
123456
5
07/02/2023 14:51
123456
9
07/02/2023 15:27
567890
0
07/02/2023 11:44
567890
4
07/02/2023 12:23
567890
5
07/02/2023 12:29
567890
5
07/02/2023 13:26
567890
5
07/02/2023 13:28
567890
5
07/02/2023 13:28
567890
5
07/02/2023 13:29
567890
9
07/02/2023 13:55
For each id in the dataset there are a number of statuses that need to be identified as 'blocks' of activity, where each block starts with a status code of 0 (and is sorted by datetime)
What I'd like to do is to add a column that identifies this block. So my data would look like this with that column added.
id
status
datetime
block
123456
0
07/02/2023 12:43
1
123456
4
07/02/2023 12:49
1
123456
5
07/02/2023 12:58
1
123456
5
07/02/2023 13:48
1
123456
7
07/02/2023 14:29
1
123456
0
07/02/2023 14:50
2
123456
4
07/02/2023 14:50
2
123456
5
07/02/2023 14:51
2
123456
9
07/02/2023 15:27
2
567890
0
07/02/2023 11:44
1
567890
4
07/02/2023 12:23
1
567890
5
07/02/2023 12:29
1
567890
5
07/02/2023 13:26
1
567890
5
07/02/2023 13:28
1
567890
5
07/02/2023 13:28
1
567890
5
07/02/2023 13:29
1
567890
9
07/02/2023 13:55
1
I've used window functions before, but I can't get my head around how to do this.

Answer 1

You may get the desired result using CTE and the below query
Sample Table:
CREATE TABLE SampleData (
id INT,
status INT,
datetime DATETIME
);
Sample Data:
INSERT INTO SampleData (id, status, datetime)
VALUES
(123456, 0, '07/02/2023 12:43'),
(123456, 4, '07/02/2023 12:49'),
(123456, 5, '07/02/2023 12:58'),
(123456, 5, '07/02/2023 13:48'),
(123456, 7, '07/02/2023 14:29'),
(123456, 0, '07/02/2023 14:50'),
(123456, 4, '07/02/2023 14:50'),
(123456, 5, '07/02/2023 14:51'),
(123456, 9, '07/02/2023 15:27'),
(567890, 0, '07/02/2023 11:44'),
(567890, 4, '07/02/2023 12:23'),
(567890, 5, '07/02/2023 12:29'),
(567890, 5, '07/02/2023 13:26'),
(567890, 5, '07/02/2023 13:28'),
(567890, 5, '07/02/2023 13:28'),
(567890, 5, '07/02/2023 13:29'),
(567890, 9, '07/02/2023 13:55');
Query:
WITH CteSampleData AS (
SELECT *,
SUM(CASE WHEN status = 0 THEN 1 ELSE 0 END)
OVER (PARTITION BY id ORDER BY datetime) AS block
FROM SampleData
)
SELECT id, status, datetime, block
FROM CteSampleData
ORDER BY id, datetime;