public function groupBy($col, /*# bool */ $rawMode = false)
    {
        if (is_array($col)) {
            foreach ($col as $c) {
                $this->groupBy($c, $rawMode);
            }
        } else {
            $this->clause_groupby[] = [
                $rawMode ?: $this->isRaw($col), $col
            ];
        }
        return $this;
    }
public function groupBy($col, /*# bool */ $rawMode = false)
    {
        if (is_array($col)) {
            foreach ($col as $c) {
                $this->groupBy($c, $rawMode);
            }
        } else {
            $this->clause_groupby[] = [
                $rawMode ?: $this->isRaw($col), $col
            ];
        }
        return $this;
    }
{@inheritDoc}