QueryDsl group by with multiple fields

Question

i m trying to include a groupBy in a queryDsl function but i can't come out with an answer.

        override fun list(
        urlRecords: RecordMap?,
        parameters: Parameters,
        orderBy: Array<out OrderSpecifier<*>>,
        limitOffset: LimitOffset
    ) = with(dal) {
        val selectActions = actions.mapValues { (_, action) ->
            action.enabledPredicate(ExpressionType.SELECT)
        }
        val queryResults = jpaQueryFactory
            .from(entityPath)
            .apply { joins.forEach { join(it) } }
            .apply { leftJoins.forEach { leftJoin(it) } }
            .apply(applyJoins)
            .select(
                QLegameAssistito.legameAssistito.assistito.id,
                QLegameAssistito.legameAssistito.inizioValidita,
                QLegameAssistito.legameAssistito.fineValidita
                )
            .apply { if (distinct != null) distinct() }
            .where(where(urlRecords), filterWhere(parameters))
            .groupBy(QLegameAssistito.legameAssistito.assistito.id,
                QLegameAssistito.legameAssistito.inizioValidita,
                QLegameAssistito.legameAssistito.fineValidita
                )
            .orderBy(*orderBy)
            .limit(limitOffset.limit)
            .offset(limitOffset.offset)
            .fetchResults()
        ListResults(selectActions, queryResults)
    }

Error:

java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: expecting CLOSE, found ',' near line 1, column 51 [select count(distinct legameAssistito.assistito.id, legameAssistito.inizioValidita, legameAssistito.fineValidita)

If you take off the groupBy,it works.Also it seems there is a problem is probably in concatenating values in the groupby as it works with just one value.