code: def to_statement()
        @api.utils_reporter.statement_builder_used()
        validate()
        ordering = @ascending ? 'ASC' : 'DESC'
        pql_query = PQLQuery.new
        pql_query << SELECT % @select unless @select.to_s.empty?
        pql_query << FROM % @from unless @from.to_s.empty?
        pql_query << WHERE % @where unless @where.to_s.empty?
        pql_query << ORDER % [@order_by, ordering] unless @order_by.to_s.empty?
        pql_query << LIMIT % @limit unless @limit.nil?
        pql_query << OFFSET % @offset unless @offset.nil?
        return {:query => pql_query.to_s(), :values => @pql_values.values}
      end
docs: Create a statement object that can be sent in a Ad Manager API request.