When using the the Serial Difference aggregation in Time Series Visual Builder, I stumble upon missing results in the visualisation. For example, I use a time interval of 1 year to compare the sum of sales data per customers between two years. If a customer purchased goods in the first year, but didn't in the second year - the difference always seems to be zero. I would like the difference to give a negative result. The same is true if the the buyer only started buying in the second year. Also a difference of 0, where I would like to see a positive difference.
I looked at the reference and noticed an option that inserts zeros in gaps. However, in TSVB this option is not available.
Edit: I'm on Elastic Cloud 6.2.0.
Is there any way I can calculate the desired difference? Any help is appreciated.