Finding the sum of the last entry given specific text in a field
Sorry for the nonsensical title.
I have a table called Bulk Inventory:
In a formula in a different table, I want to find the sum of the 'Cumulative (Laa)' values for the final entry of a given month for all tanks. So from the screenshot above, I want to add 10.14 plus 4.00 and so on.
I want the formula to work even if I add more tanks in the future.
By the way, loving Ninox so far! Once I have my database set up it's going to save me almost an hour per day on average!

Hi Alex,
just summarise all the separate values for one month, i.e. 0.00, 10.14, 40.00, 30.00 ... that will yield the same result and you can easily access these values with a select command on the Tank table and an appropriate month filter. It will go over all the Tanks in the table, no matter how many you'll add or remove
It will be something like
sum((select Tank where month(date) = 2).fieldThatYouCumulate)
Does this help?

I think I didn't state my problem clearly enough, but I've found a solution:
let a := this; let b := unique((select 'Bulk Inventory' where month(Date) = a.Month).Tank); let total := 0; let i := 0; while i < count(b) do total := total + last(select 'Bulk Inventory' where Tank = item(b, i)).'Cumulative (Laa)'; i := i + 1 end ; total