Future forecasting based on a multiplier in BigQuery

Question

I am trying to do semi forecasting with BigQuery. I have minutely data of users, and a minute multiplier (pre calculated based on past events) that should predict the next minute's value. I created a dataset with all future minutes for the relevant timeframe, future minute will have null value, it looks like that:

Now trying to calculate all future values based on the multiplier. I can't figure out how to apply this to more than 1 row, meaning; the first null row will be the prev value times the multiplier. But now what? How can I keep calculating it based on future values? The output should look like that:

So 100 is the only real value - then 100 * 1.1 will be 120, and then 120 * 1.2 will be 132, so on and so forth.

Appreciate the help guys, thanks!

Answer 1

Do you think there is another way to solve this then?

Consider below approach

select *,
  round(first_value(value/multiplier) over win * exp(sum(ln(multiplier)) over win), 2) as new_value
from your_table
window win as (order by minute)       

if applied to sample data in your question - output is