Encore\Admin\Grid\Model::setRelationSort PHP Method

    protected function setRelationSort($column)
    {
        list($relationName, $relationColumn) = explode('.', $column);
        if ($this->queries->contains(function ($key, $query) use($relationName) {
            return $query['method'] == 'with' && in_array($relationName, $query['arguments']);
        })) {
            $relation = $this->model->{$relationName}();
            $this->queries->push(['method' => 'join', 'arguments' => $this->joinParameters($relation)]);
            $this->queries->push(['method' => 'orderBy', 'arguments' => [$relation->getRelated()->getTable() . '.' . $relationColumn, $this->sort['type']]]);
        }
    }