Normaly I trac all my consuption in a GSheet, but how do I substract the ald consumtion from the new one ?
Hello, @Robert_K, welcome to the community!
There is thread about how to do calculations with other rows.
However, you have one record for each month, I would prefer just filter previous month’s value:
This formula finds previous month by calling
thisRow.Date.RelativeDate(-1).DateTimeTruncate("month") and then runs
Filter() for all rows in the table to select a row where its
Date.DateTimeTruncate("month") is equal to the previous month of the current row.
Then formula extracts
Value field. The result is still a list, not a single value (despite in this case there is a list with one value). So, we need to call
First() to get first element. If this list was empty,
Blank, so we need an additional check and substitution with
IfBlank(). I assume there is default value of 0 if no previous month present, but you can replace 0 by
Value to make Difference = 0 in this case.
Then this all calculations should be subtracted from
thisRow.Value to get a difference.
P.S. I’ve also added conditional format to exclude months duplicates.