Add a grouping column to the GROUP clause of the query.

@param   mixed  $columns  A string or array of ordering columns.
@return   Query  Returns this object to allow chaining.
167696
public function group($columns)
  {
    if ( is_null($this->group) ){
      $this->group = new Element('GROUP BY', $columns);
    }
    else {
      $this->group->append($columns);
    }

    return $this;
  }
705695
public function columns(array $columns): self
    {
        foreach ($columns as $name => $alias) {
            if (!is_string($name)) {
                $this->column($alias, null);
                continue;
            }
            if (is_string($alias)) {
                $this->column($name, $alias);
            } else {
                $this->column($alias, $name);
            }
        }
        return $this;
    }
966286
public function setMultiple(array $columns)
    {
        foreach ($columns as $column => $value) {
            $this->set($column, $value);
        }

        return $this;
    }
1373523
public function group($columns)
    {
        settype($columns, 'array'); //force to an array

        $this->group = array_unique(array_merge($this->group, $columns));
        return $this;
    }
273437
public static function all( $columns = ['*'] )
	{
		$columns = is_array( $columns ) ? $columns : func_get_args();

		$instance = new static;

		return $instance->newQuery()->get( $columns );
	}
742852
public function order($columns)
    {
        foreach ($columns as $column => $position) {
            $this->positions[$column] = $position;
        }

        return $this;
    }
672988
public function addGroupBy($column, $sort = null)
        {
            if (is_array($column)) {
                foreach ($column as $single_column) {
                    $this->addGroupBy($single_column[0], $single_column[1]);
                }
            } else {
                $this->sort_groups[] = new QueryColumnSort($column, $sort);
            }

            return $this;
        }
1278871
public function addSortableColumn($columns)
    {
        if ($this->data) {
            foreach ($this->data as $id => $field) {
                if ($field->admin_column_sortable) {
                    $columns[$id] = $field->label;
                }
            }
        }

        return $columns;
    }
1116470
public function addColumns(array $columns)
    {
        /*
         * Build a final collection of list column objects
         */
        foreach ($columns as $columnName => $config) {
            $this->allColumns[$columnName] = $this->makeListColumn($columnName, $config);
        }
    }
746190
public function columns(array $columns)
	{
		$columnsArray = array();
		foreach($columns as $column)
		{
			$columnsArray[] = $this->factory->references('Column', $column);
		}
		$this->insert->columns($columnsArray);

		return $this;
	}
949880
public function addIndex($columns)
    {
        $index = new Index($columns, $this);

        $this->actions[] =  function () use ($index) {
             return $this->manipulation->create($index);
        };

        return $this;
    }
165129
public function columns($columns){
        if(is_array($columns)) $this->columns = array_merge($this->columns,$columns);
        return self::getInstance();
    }
653329
public function columns($columns)
    {
        if (!is_array($columns)) {
            $columns = preg_split('~\s*,\s*~', trim($columns));
        }

        $this->columns = $columns;

        return $this;
    }
933073
function columns(array $columns)
    {
        foreach ($columns as &$col) {
            if (!$col instanceof Attribute) {
                $col = new UnqualifiedColumn($col);
            }
        }
        $this->nodes->columns = $columns;
        return $this;
    }
711120
public function targetColumns($columns) {
        $this->targetColumns = is_array($columns) ? $columns : explode(',',
                        $columns);
        return $this;
    }
694026
public function group($columns)
    {
        if (null === $this->group) {
            $this->group = $this->element('GROUP BY', $columns);
        } else {
            $this->group->append($columns);
        }

        return $this;
    }
1197780
public function select($columns = [])
    {
        $columns = is_array($columns) ? $columns : func_get_args();

        if (! empty($columns)) {
            $this->columns = $columns;
        }

        return $this;
    }