SQL access only a single expression can be used with GROUP BY

I'm testing the Elasticsearch 6.3 / SQL Access, and I got a planning_exception message: Currently, only a single expression can be used with GROUP BY.
Do any one know when it will be solved in Elastic plan? Or how I can solve it by self in sql access?

Hi @Jack_Wu,

Indeed, in ES 6.3 this was not possible, but the restriction has been removed starting with ES 6.4.
For your reference this is the GH issue covering this.