public function select($columns)
    {
        if (is_array($columns)) {
            $this->columns = $columns;
        } elseif ($columns === '*') {
            $this->columns = ['*'];
        }
        return $this;
    }
public function select($columns)
    {
        if (is_array($columns)) {
            $this->columns = $columns;
        } elseif ($columns === '*') {
            $this->columns = ['*'];
        }
        return $this;
    }
public function select ( $ columns ) { if ( is_array ( $ columns ) ) { $ this -> columns = $ columns ; } elseif ( $ columns === '*' ) { $ this -> columns = [ '*' ] ; } return $ this ; }
Sets the columns to be selected

@param array $columns Columns to select
@return object Database instance
Sets the columns to be selected