compute_column_widths

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 155
        def compute_column_widths(result)
          [].tap do |widths|
            result.columns.each_with_index do |column, i|
              cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? 'NULL' : r[i].to_s}
              widths << cells_in_column.map(&:length).max
            end
          end
        end