Is it possible to have a key script field (term scripts) in the Terms Stats
facet, similar to there is in Terms facet?
The documentation for Terms Stats facet says it combines terms and stats
facet. However, I can't find a way to use a term script.
My use case is I want to get stats of a numeric field against a string made
by concatenating several fields: like doc['f1'].value + ',' +
doc['f2'].value + ...