By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
INSERT 0 7
| client | product | dt | grp | consecutive_months |
|---|---|---|---|---|
| 1 | Sub | 2020-10-01 00:00:00 | 24249 | 1 |
| 1 | Sub | 2020-11-01 00:00:00 | 24249 | 2 |
| 1 | Sub | 2021-01-01 00:00:00 | 24250 | 1 |
| 1 | Sub | 2021-02-01 00:00:00 | 24250 | 2 |
| 2 | Sub | 2020-11-01 00:00:00 | 24250 | 1 |
| 2 | Sub | 2020-12-01 00:00:00 | 24250 | 2 |
| 2 | Sub | 2021-02-01 00:00:00 | 24251 | 1 |
SELECT 7