Forecast and grouping

[kprotrka]

I have field BETRAG and it is filled per ID till the current month(07). Now I need to make the forecast till the end of the year.

I need to take last non null value from ID and show it till the end of the year. Example:

ID     BETRAG       YEAR_MONTH

1            100                      2021-06

1              0                           2021-07

here i need to take 100 from the August till December.

ID     BETRAG       YEAR_MONTH

2            300                      2021-06

2            400                       2021-07

For this ID need to take 400 from August till December.

Anyone has any idea?