How to calculate the percentage change over a month based on delta?

[hqw]

hi all,

I want a new column which calculates the percentage change over a month. In the below snapshot, the change rate should equal to the diff/sum of last month. One example is percentage=41703/299981.
however, if I add a new command behind :|eval percentage=round(dif/sum,1), it will calculate by 41703/341684, which is not correct.

could any one help me out of this?

thanks in advance.

[martin_mueller · Accepted solution]

Replace your delta with this:

... | streamstats current=f window=1 last(sum) as last_sum | eval dif = sum - last_sum | eval percentage = round(dif/last_sum, 1)