When passing a field name to a function, do not use the ‘ symbol within the jKQL query.
For example:
Get events fields avg(elapsedtime), min(elapsedtime), max(elapsedtime) where elapsedtime exists and starttime between '2018-12-10 0:0:0' and '2019-12-31 23:59:59' group by starttime bucketed by day show as anomalychart