public function groupedBy(string ... $groupingColumnNames)
    {
        foreach ($groupingColumnNames as $name) {
            $this->groupingColumns[$name] = $this->table->getColumn($name);
        }

        return $this;
    }
public function groupedBy(string ... $groupingColumnNames)
    {
        foreach ($groupingColumnNames as $name) {
            $this->groupingColumns[$name] = $this->table->getColumn($name);
        }

        return $this;
    }
public function groupedBy ( string ... $ groupingColumnNames ) { foreach ( $ groupingColumnNames as $ name ) { $ this -> groupingColumns [ $ name ] = $ this -> table -> getColumn ( $ name ) ; } return $ this ; }
Sets the column which the order indexes are grouped by.

@param \string[] $groupingColumnNames

@return static
@internal param $string ... $groupingColumnNames
Sets the column which the order indexes are grouped by .