Transformation - Binary Operation - Remove Null (0) results

i am using influxDB to store some Values from ioBroker PV-Forecast.

Those values are fetched in 2 queries from influxDB and should be added.
Means: 150Wh from Query A with 150Wh from Query B result in 300Wh, which works so far.

But for some hours, special the night ones :wink: , there are no forecast values - therefor they are null or do not exist.

How is it possible, to remove the graph for those ones?

Example here:

Thank you!