#434

2026-10-26 21:53:09 +09:00
@@ -4,7 +4,7 @@ class CountsTablesController < ApplicationController
    definition = CountsResourceDefinition.new(params[:resource])
    render json: { fields: definition.metadata,
                   axes: { latest: definition.axes(false), history: definition.axes(true) },
-                   grains: CountsAxes::GRAINS }
+                   grains: CountsAxes::GRAINS, defaults: CountsDefaults.metadata(params[:resource]) }
  rescue ArgumentError
    head :bad_request
  end
@@ -40,7 +40,7 @@ class CountsAxes
  end

  def expressions
-    all.map do |axis|
+    @expressions ||= all.map do |axis|
      field = axis.fetch('field')
      case field
      when 'tags'
@@ -56,9 +56,9 @@ class CountsAxes
    end
  end

-  def joins
+  def joins(fields = all.map { _1['field'] })
    result = ''
-    if all.any? { _1['field'] == 'tags' }
+    if fields.include?('tags')
      result += <<~SQL.squish
         JOIN JSON_TABLE(CAST(v.tags_json AS JSON), '$[*]' COLUMNS (
          tag_id BIGINT PATH '$.tag_id' NULL ON EMPTY,
@@ -66,7 +66,7 @@ class CountsAxes

      SQL
    end
-    if all.any? { _1['field'] == 'changed_field' }
+    if fields.include?('changed_field')
      fields = @definition.changes.map do |field|
        "SELECT #{ ApplicationRecord.connection.quote(field) } AS field_key"
      end.join(' UNION ALL ')
@@ -89,6 +89,8 @@ class CountsAxes
      raise ArgumentError unless @definition.axes(@population.history).include?(axis['field'])
      if @definition.fields[axis['field']] == :datetime
        raise ArgumentError unless GRAINS.include?(axis.fetch('grain', 'month'))
+
+        axis['grain'] ||= 'month'
      elsif axis.key?('grain')
        raise ArgumentError
      end
@@ -0,0 +1,46 @@
+# Only confirmed combinations belong here; all others retain the existing behaviour.
+class CountsDefaults
+  POST_COLUMNS = ['resource_id', 'version_no', 'is_latest', 'title', 'url',
+                  'thumbnail_base', 'tags', 'parents', 'original_created_from',
+                  'original_created_before', 'event_type', 'user', 'created_at'].freeze
+
+  def self.entries(resource)
+    result = [{ definition: 'history', mode: 'summary', params: {
+        'rows' => [{ field: 'created_at', grain: 'month' }].to_json,
+        'cols' => [{ field: 'event_type' }].to_json,
+        'sort' => 'a0:desc', 'conditions' => '[]' } }]
+    if resource == 'posts'
+      result += [{ definition: 'latest', mode: 'summary', params: {
+          'rows' => '[]', 'cols' => '[]', 'conditions' => '[]', 'tags' => '' } },
+          { definition: 'latest', mode: 'details', params: {
+              'columns' => POST_COLUMNS.join(','), 'order' => POST_COLUMNS.join(','),
+              'children' => 'tags.name,parents.id', 'nested_json' => '0',
+              'conditions' => '[]', 'tags' => '' } }]
+    end
+    result
+  end
+
+  def self.for(params)
+    settings = entries(params.fetch('resource', 'posts')).find do |entry|
+      entry[:definition] == params.fetch('definition', 'latest') &&
+          entry[:mode] == params.fetch('mode', 'summary')
+    end&.fetch(:params) || {}
+    if settings.key?('sort') && params.key?('rows')
+      actual = JSON.parse(params['rows'])
+      expected = JSON.parse(settings.fetch('rows'))
+      compatible = actual.is_a?(Array) && actual.first.is_a?(Hash) &&
+          actual.first['field'] == expected.first['field'] &&
+          actual.first.fetch('grain', 'month') == expected.first['grain']
+      unless compatible
+        settings = settings.except('sort')
+      end
+    end
+    settings
+  end
+
+  def self.metadata(resource)
+    entries(resource).map do |entry|
+      entry.merge(params: entry[:params].map { |key, value| { key:, value: } })
+    end
+  end
+end
@@ -6,7 +6,6 @@ class CountsExportProjection
                'is_latest' => 'is_latest', 'thumbnail' => 'thumbnail_url',
                'thumbnail_base' => 'thumbnail_base', 'title' => 'title', 'url' => 'url',
                'tags' => 'tags', 'parents' => 'parents', 'video_ms' => 'video_ms',
-                'original_created_at' => 'original_created_at',
                'original_created_from' => 'original_created_from',
                'original_created_before' => 'original_created_before',
                'user' => 'created_by_user', 'created_at' => 'created_at',
@@ -43,6 +42,9 @@ class CountsExportProjection
  attr_reader :columns, :headers

  def initialize(params, resource:, summary:, tags:)
+    if params.key?('definition')
+      params = CountsDefaults.for(params.merge('resource' => resource)).merge(params)
+    end
    @params = params
    @labels = JSON.parse(params.fetch('labels', '{}'))
    raise ArgumentError unless @labels.is_a?(Hash) && @labels.length <= 100
@@ -103,8 +105,6 @@ class CountsExportProjection
      else
        value = case key
                when 'thumbnail' then row[:thumbnail_base]
-                when 'original_created_at'
-                  { from: row[:original_created_from], before: row[:original_created_before] }
                else row[ROOT_KEYS.fetch(key).to_sym]
                end
        value = nested(value || [], CHILDREN.fetch(key), key) if CHILDREN.key?(key)
@@ -0,0 +1,28 @@
+# Coordinates carry their aggregation depth; SQL NULL remains an ordinary axis value.
+class CountsPivotLayout
+  def self.depths(keys, sorts, measures: true)
+    return [] if keys.length < 2 || sorts.first&.first == 'count' ||
+        sorts.first&.first&.start_with?('measure_')
+
+    relevant = sorts.map(&:first).select { keys.include?(_1) || (measures && (_1 == 'count' ||
+        _1.start_with?('measure_'))) }
+    order = (relevant + keys).uniq
+    (1...keys.length).select { order.first(_1).sort == keys.first(_1).sort }
+  end
+
+  def self.headers(values, depths, next_values: nil, grand: false)
+    result = []
+    values.each_with_index do |tuple, index|
+      result << { values: tuple, kind: 'data' }
+      following = values[index + 1] || next_values
+      depths.reverse_each do |depth|
+        prefix = tuple.first(depth)
+        next if following && following.first(depth) == prefix
+
+        result << { values: prefix, kind: 'subtotal' }
+      end
+    end
+    result << { values: [], kind: 'grand_total' } if grand
+    result
+  end
+end
@@ -0,0 +1,59 @@
+# Re-aggregate the population, never add up already grouped cells (multi-value axes overlap).
+class CountsPivotTotals
+  def initialize(population, axes, row_headers, column_headers)
+    @population = population
+    @axes = axes
+    @rows = row_headers.group_by { _1[:values].length }
+    @columns = column_headers.group_by { _1[:values].length }
+  end
+
+  def call
+    queries = @rows.flat_map do |row_depth, headers|
+      @columns.filter_map do |column_depth, columns|
+        next if row_depth == @axes.rows.length && column_depth == @axes.columns.length
+
+        indexes = (0...row_depth).to_a +
+            (0...column_depth).map { @axes.rows.length + _1 }
+        expressions = indexes.map { @axes.expressions[_1] }
+        scope = @population.scope.except(:select, :order)
+        joins = @axes.joins(indexes.map { @axes.all[_1].fetch('field') })
+        scope = scope.joins(joins) unless joins.empty?
+        if row_depth.positive?
+          tuples = headers.map { _1[:values] }.uniq
+          predicate = tuples.map { Array.new(row_depth) { |i|
+            "(#{ expressions[i] }) <=> ?"
+          }.join(' AND ') }.map { "(#{ _1 })" }.join(' OR ')
+          scope = scope.where(predicate, *tuples.flatten)
+        end
+        if column_depth.positive?
+          tuples = columns.map { _1[:values] }.uniq
+          predicate = tuples.map { Array.new(column_depth) { |i|
+            "(#{ expressions[row_depth + i] }) <=> ?"
+          }.join(' AND ') }.map { "(#{ _1 })" }.join(' OR ')
+          scope = scope.where(predicate, *tuples.flatten)
+        end
+        grouped = expressions.each_with_index.map { |expression, index|
+          "#{ expression } AS v#{ index }"
+        }
+        # Fixed-width result coordinates, independent of NULL and of translated labels.
+        padding = (expressions.length...@axes.all.length).map { "NULL AS v#{ _1 }" }
+        fields = ["#{ row_depth } AS row_depth", "#{ column_depth } AS column_depth"] +
+            grouped + padding + ['COUNT(DISTINCT v.id) AS count']
+        scope = scope.group(*expressions.map { Arel.sql(_1) }) if expressions.any?
+        scope.optimizer_hints('MAX_EXECUTION_TIME(10000)')
+            .select(Arel.sql(fields.join(', '))).to_sql
+      end
+    end
+    return [] if queries.empty?
+
+    sql = queries.map { "(#{ _1 })" }.join(' UNION ALL ')
+    @population.definition.model.connection.select_all(
+        "SELECT /*+ MAX_EXECUTION_TIME(10000) */ * FROM (#{ sql }) totals").map do |record|
+      row_depth = record['row_depth'].to_i
+      column_depth = record['column_depth'].to_i
+      { row: (0...row_depth).map { record["v#{ _1 }"] },
+        column: (0...column_depth).map { record["v#{ row_depth + _1 }"] },
+        count: record['count'].to_i }
+    end
+  end
+end
@@ -5,7 +5,7 @@ class CountsQuery
  COLUMNS = {
      'posts' => COMMON_COLUMNS + [
          'thumbnail', 'thumbnail_base', 'title', 'url', 'tags', 'parents', 'video_ms',
-          'original_created_at', 'original_created_from', 'original_created_before'],
+          'original_created_from', 'original_created_before'],
      'tags' => COMMON_COLUMNS + [
          'name', 'names', 'category', 'aliases', 'parents', 'deprecated'] }.freeze
  KEYS = [
@@ -124,8 +124,6 @@ class CountsQuery
          'title', 'url', 'thumbnail_base', 'video_ms',
          'original_created_from', 'original_created_before']
      common.merge(fields.to_h { [_1, ["#{ @table }.#{ _1 }"]] }).merge(
-          'original_created_at' => [
-              'post_versions.original_created_from', 'post_versions.original_created_before'],
          'tags' => json_order('post_versions.tags_json'),
          'parents' => list_order('post_versions.parent_post_ids'))
    else
@@ -10,6 +10,7 @@ class CountsTableExport
    raise ArgumentError if (params.keys - CountsTableQuery::KEYS - EXTRA).any?
    raise ArgumentError unless params.values.all? { _1.is_a?(String) }

+    params = CountsDefaults.for(params).merge(params)
    unless params.key?('children')
      params = params.merge('children' => CountsExportProjection.default_children(
          params.fetch('resource', 'posts')).join(','))
@@ -63,7 +64,8 @@ class CountsTableExport
          total = @summary ? nil : page[:count]
          progress&.call(processed, total)
          unless started
-            metadata = page.except(:versions, :cells, :axis_labels, :column_values).merge(
+            metadata = page.except(:versions, :cells, :axis_labels, :column_values,
+                :row_headers, :column_headers, :pivot_totals).merge(
                resource:, filters: @params.slice(*CountsTableQuery::KEYS),
                fields: @query.population.definition.metadata,
                columns: @columns, column_labels: @headers,
@@ -71,12 +73,35 @@ class CountsTableExport
                sort: @params.fetch('sort', ''), child_sort: @params['child_sort'])
            output << (format == 'json' ? "{\"metadata\":#{ metadata.to_json },\"data\":[" : "\uFEFF")
            if format == 'csv'
-              headers = @summary ? summary_headers : @headers
-              output << CSV.generate_line(headers.map { safe(_1) }, row_sep: "\r\n")
+              headings = @summary ? pivot_headers(page) : [@headers]
+              headings.each do |headers|
+                output << CSV.generate_line(headers.map { safe(_1) }, row_sep: "\r\n")
+              end
            end
            started = true
          end
-          (page[:cells] || page[:versions]).each do |row|
+          if @summary
+            pivot_rows(page).each do |header|
+              records = page.fetch(:column_headers).map { pivot_cell(header, _1, page) }
+              if format == 'csv'
+                labels = pivot_row_labels(header, page)
+                values = labels + records.map { _1[:count] }
+                output << CSV.generate_line(values.map { safe(_1) }, row_sep: "\r\n")
+                processed += records.length
+                progress&.call(processed, nil)
+              else
+                records.each do |record|
+                  output << ',' unless first
+                  output << record.to_json
+                  first = false
+                  processed += 1
+                  progress&.call(processed, nil)
+                end
+              end
+            end
+            next
+          end
+          page[:versions].each do |row|
            record = project(row)
            if format == 'json'
              output << ',' unless first
@@ -106,12 +131,76 @@ class CountsTableExport

  private

-  def summary_headers
-    return @headers if @headers.any?
+  def pivot_rows(page)
+    page.fetch(:row_headers).reject do |header|
+      header[:kind] == 'grand_total' && @query.page * @query.limit < page[:group_count]
+    end
+  end

-    labels = @labels
-    @query.axes.all.map { labels.fetch(_1['field'], _1['field']) } +
-        [labels.fetch('count', 'count')]
+  def total_label(header)
+    @labels.fetch(header[:kind] == 'grand_total' ? 'grandTotal' : 'subtotal', '')
+  end
+
+  def pivot_row_labels(header, page)
+    values = header[:values].each_with_index.map { |value, index|
+      summary_value(value, index, page)
+    }
+    values << total_label(header) unless header[:kind] == 'data'
+    leading = [@query.axes.rows.length, @query.axes.columns.any? ? 1 : 0].max
+    Array.new(leading) { values[_1] || '' }
+  end
+
+  def pivot_headers(page)
+    row_count = @query.axes.rows.length
+    cols = @query.axes.columns
+    leading = [row_count, cols.any? ? 1 : 0].max
+    columns = page.fetch(:column_headers)
+    Array.new([cols.length, 1].max) do |level|
+      prefix = Array.new(leading) { level.zero? ? @headers[_1].to_s : '' }
+      prefix = [''] if row_count.zero? && cols.any?
+      prefix + columns.each_with_index.map do |header, index|
+        values = header[:values]
+        if cols.empty?
+          header[:kind] == 'data' ? @labels.fetch('count', '') : total_label(header)
+        elsif level == values.length && header[:kind] != 'data'
+          total_label(header)
+        elsif level < values.length
+          previous = index.positive? ? columns[index - 1][:values] : nil
+          if level < cols.length - 1 && previous && previous.first(level + 1) == values.first(level + 1)
+            ''
+          else
+            summary_value(values[level], row_count + level, page)
+          end
+        else
+          ''
+        end
+      end
+    end
+  end
+
+  def pivot_cell(row, column, page)
+    @pivot_lookup ||= {}
+    # Discard the previous page's lookup; memory remains bounded by one page and its rollups.
+    unless @pivot_page.equal?(page)
+      @pivot_page = page
+      @pivot_lookup = page.fetch(:cells).to_h do |cell|
+        values = cell[:values]
+        [[values.first(@query.axes.rows.length), values.drop(@query.axes.rows.length)], cell[:count]]
+      end
+      page.fetch(:pivot_totals).each { @pivot_lookup[[_1[:row], _1[:column]]] = _1[:count] }
+    end
+    kinds = [row[:kind], column[:kind]]
+    kind = if kinds.include?('grand_total')
+             'grand_total'
+           elsif kinds.include?('subtotal')
+             'subtotal'
+           else
+             'data'
+           end
+    { row: row[:values], column: column[:values], kind:,
+      row_kind: row[:kind], column_kind: column[:kind],
+      row_depth: row[:values].length, column_depth: column[:values].length,
+      count: @pivot_lookup.fetch([row[:values], column[:values]], 0) }
  end

  def summary_value(value, index, page)
@@ -12,6 +12,7 @@ class CountsTableQuery
    raise ArgumentError if (params.keys - KEYS).any?
    raise ArgumentError unless params.values.all? { _1.is_a?(String) }

+    params = CountsDefaults.for(params).slice(*KEYS).merge(params)
    @params = params
    @population = CountsPopulation.new(params)
    @definition = population.definition
@@ -26,7 +27,7 @@ class CountsTableQuery
    @sort = params.fetch('sort', '').split(',').map { _1.split(':', -1) }
    allowed = mode == 'summary' ? axes.all.each_index.map { "a#{ _1 }" } + ['count'] :
        @definition.fields.keys + ['is_latest'] +
-        (@definition.resource == 'posts' ? ['tags', 'parents', 'original_created_at'] : []) +
+        (@definition.resource == 'posts' ? ['tags', 'parents'] : []) +
        (@definition.resource == 'tags' ? ['parents', 'deprecated'] : [])
    raise ArgumentError if @sort.map(&:first).uniq.length != @sort.length
    @sort.each do |key, direction, *extra|
@@ -72,25 +73,26 @@ class CountsTableQuery
    # Page whole row tuples so a pivot row is never split across display pages.
    row_selection = row_keys.empty? ? '1 AS singleton' : row_keys.join(', ')
    row_group = row_keys.empty? ? 'GROUP BY singleton' : "GROUP BY #{ row_keys.join(', ') }"
+    measure_joins = []
+    extras = []
    row_sort = @sort.each_with_index.filter_map do |(key, direction), index|
      if key == 'count' || key.start_with?('measure_')
-        condition = if key == 'count'
-                      'TRUE'
-                    else
-                      measure_values(key).each_with_index.map do |value, offset|
-                        "a#{ axes.rows.length + offset } <=> #{ @connection.quote(value) }"
-                      end.join(' AND ').presence || 'TRUE'
-                    end
-        ["MAX(CASE WHEN #{ condition } THEN count END) AS sort#{ index }",
-         "sort#{ index } IS NULL ASC, sort#{ index } #{ direction.upcase }"]
+        values = key == 'count' ? [] : measure_values(key)
+        relation = measure_relation(values)
+        matches = row_keys.map { "grouped.#{ _1 } <=> sort#{ index }.#{ _1 }" }
+        condition = matches.empty? ? 'TRUE' : matches.join(' AND ')
+        measure_joins << "LEFT JOIN (#{ relation }) sort#{ index } ON #{ condition }"
+        extras << "sort#{ index }.count AS sort#{ index }"
+        "sort#{ index } IS NULL ASC, sort#{ index } #{ direction.upcase }"
      elsif row_keys.include?(key)
-        [nil, "#{ key } IS NULL ASC, #{ key } #{ direction.upcase }"]
+        "#{ key } IS NULL ASC, #{ key } #{ direction.upcase }"
      end
    end
-    extras = row_sort.filter_map(&:first)
-    order_rows = row_sort.map(&:last) + row_keys.map { "#{ _1 } IS NULL, #{ _1 }" }
+    order_rows = row_sort + row_keys.map { "#{ _1 } IS NULL, #{ _1 }" }
    order_rows = ['singleton ASC'] if order_rows.empty?
-    group_sql = "SELECT #{ ([row_selection] + extras).join(', ') } FROM cells #{ row_group }"
+    grouped = "SELECT #{ row_selection } FROM cells #{ row_group }"
+    selection = (['grouped.*'] + extras).join(', ')
+    group_sql = "SELECT #{ selection } FROM (#{ grouped }) grouped #{ measure_joins.join(' ') }"
    total = @connection.select_value(<<~SQL).to_i
      #{ prefix }
      SELECT /*+ MAX_EXECUTION_TIME(10000) */ COUNT(*) FROM (#{ group_sql }) row_groups
@@ -113,7 +115,30 @@ class CountsTableQuery
      SELECT /*+ MAX_EXECUTION_TIME(10000) */ cells.* FROM cells JOIN page_rows ON #{ join }
      ORDER BY #{ order.join(', ') }
    SQL
-    { group_count: total, column_values:, cells: records.map do |row|
+    next_row = @connection.select_one(<<~SQL)
+      #{ prefix }, row_groups AS (#{ group_sql }),
+      numbered AS (SELECT row_groups.*,
+        ROW_NUMBER() OVER (ORDER BY #{ order_rows.join(', ') }) AS position FROM row_groups)
+      SELECT /*+ MAX_EXECUTION_TIME(10000) */ * FROM numbered
+      WHERE position = #{ page * limit + 1 }
+    SQL
+    row_values = records.map { |record| row_keys.map { record[_1] } }.uniq
+    row_depths = CountsPivotLayout.depths(row_keys, @sort)
+    column_keys = axes.columns.each_index.map { "a#{ axes.rows.length + _1 }" }
+    column_depths = CountsPivotLayout.depths(column_keys, @sort, measures: false)
+    row_headers = CountsPivotLayout.headers(row_values, row_depths,
+        next_values: next_row && row_keys.map { next_row[_1] }, grand: axes.rows.any?)
+    if axes.rows.empty? && axes.columns.any?
+      row_headers = [{ values: [], kind: 'grand_total' }]
+    end
+    column_headers = CountsPivotLayout.headers(column_values, column_depths,
+        grand: axes.columns.any?)
+    if axes.columns.empty? && axes.rows.any?
+      column_headers = [{ values: [], kind: 'grand_total' }]
+    end
+    totals = CountsPivotTotals.new(population, axes, row_headers, column_headers).call
+    { group_count: total, column_values:, row_headers:, column_headers:, pivot_totals: totals,
+      cells: records.map do |row|
        { values: axes.all.each_index.map { row["a#{ _1 }"] }, count: row['count'].to_i }
      end, axis_labels: axis_labels(records, column_values) }
  end
@@ -167,7 +192,11 @@ class CountsTableQuery
    keys = axes.columns.each_index.map { "a#{ axes.rows.length + _1 }" }
    return [[]] if keys.empty?

-    order = keys.map { "#{ _1 } IS NULL, #{ _1 }" }.join(', ')
+    configured = @sort.select { |key, _direction| keys.include?(key) }
+    directions = (configured + keys.map { [_1, 'asc'] }).uniq { _1.first }
+    order = directions.map { |key, direction|
+      "#{ key } IS NULL ASC, #{ key } #{ direction.upcase }"
+    }.join(', ')
    values = @connection.select_rows(<<~SQL)
      #{ prefix }
      SELECT /*+ MAX_EXECUTION_TIME(10000) */ DISTINCT #{ keys.join(', ') } FROM cells
@@ -178,9 +207,26 @@ class CountsTableQuery
    values
  end

+  def measure_relation(values)
+    row_expressions = axes.expressions.first(axes.rows.length)
+    source = population.scope.except(:select, :order)
+    fields = axes.rows + axes.columns.first(values.length)
+    joins = axes.joins(fields.map { _1.fetch('field') })
+    source = source.joins(joins) unless joins.empty?
+    values.each_with_index do |value, index|
+      expression = axes.expressions[axes.rows.length + index]
+      source = source.where("(#{ expression }) <=> ?", value)
+    end
+    selected = row_expressions.each_with_index.map { |expression, index|
+      "#{ expression } AS a#{ index }"
+    } + ['COUNT(DISTINCT v.id) AS count']
+    source = source.group(*row_expressions.map { Arel.sql(_1) }) if row_expressions.any?
+    source.select(Arel.sql(selected.join(', '))).to_sql
+  end
+
  def measure_values(key)
    value = JSON.parse([key.delete_prefix('measure_')].pack('H*'))
-    unless (value.is_a?(Array) && value.length == axes.columns.length &&
+    unless (value.is_a?(Array) && value.length <= axes.columns.length &&
        value.all? { _1.nil? || _1.is_a?(String) || _1.is_a?(Numeric) })
      raise ArgumentError
    end
@@ -190,8 +236,7 @@ class CountsTableQuery
  def detail_expression(key)
    return "(#{ population.latest_sql })" if key == 'is_latest'
    aliases = { 'tags' => 'tags_json', 'parents' => @definition.resource == 'posts' ?
-        'parent_post_ids' : 'parent_tag_ids', 'deprecated' => 'deprecated_at',
-                'original_created_at' => 'original_created_from' }
+        'parent_post_ids' : 'parent_tag_ids', 'deprecated' => 'deprecated_at' }
    field = aliases.fetch(key, key)
    expression = @definition.expression(field)
    return expression unless @definition.fields[field] == :json
@@ -1,4 +1,4 @@
-import { useEffect, useId, useState } from 'react'
+import { useEffect, useId, useRef, useState } from 'react'

 import CountsAdditionalConditions from '@/components/counts/CountsAdditionalConditions'
 import CountsAxes from '@/components/counts/CountsAxes'
@@ -9,10 +9,10 @@ import FormField from '@/components/common/FormField'
 import HelpPopover from '@/components/common/HelpPopover'
 import TagInput from '@/components/common/TagInput'
 import { Button } from '@/components/ui/button'
-import { countsUseLatest, fieldsForCounts, normaliseCountsParams,
+import { countsUseLatest, fieldsForCounts, normaliseCountsParams, readCountSort,
 	 selectedCountChildren, selectedCountColumns } from '@/lib/counts'
 import { countsNestedIsScalar } from '@/lib/countsDisplay'
-import { useCountsDefinition } from '@/lib/countsDefinitions'
+import { readCountsJSON, useCountsDefinition } from '@/lib/countsDefinitions'
 import { useClientMotion } from '@/lib/useClientMotion'
 import { inputClass } from '@/lib/utils'
 import { useUITranslation } from '@/lib/useUITranslation'
@@ -42,6 +42,7 @@ const CountsControls = (
  const nestedJSON = applied.get ('nested_json')
  const rowNumbers = applied.get ('row_numbers')
  const thumbnail = selectedCountColumns (resource, applied, definition).includes ('thumbnail')
+  const previousThumbnail = useRef (thumbnail)
  const mode = draft.get ('mode') ?? 'summary'
  const columns = selectedCountColumns (resource, draft, definition)
  const details = mode === 'details'
@@ -50,8 +51,10 @@ const CountsControls = (
      && !countsNestedIsScalar (field.children, field.key, draft)
      && field.children.some (child => selectedCountChildren (draft)
 	  .has (`${field.key}.${child.key}`)))
-  // Immediate presentation changes merge into the pending query, never replace it.
+  // Preserve absent columns until a real presentation change or an explicit edit.
  useEffect (() => {
+    if (previousThumbnail.current === thumbnail) return
+    previousThumbnail.current = thumbnail
    setDraft (previous => {
      const next = new URLSearchParams (previous)
      const columns = selectedCountColumns (resource, previous, definition)
@@ -75,16 +78,26 @@ const CountsControls = (
  const history = draft.get ('definition') === 'history'
  const update = (key: string, value: string) => setDraft (previous => {
    const next = new URLSearchParams (previous)
-    if (['mode', 'rows', 'cols'].includes (key)) next.delete ('sort')
+    if (['rows', 'cols'].includes (key) && next.get ('sort') !== '') next.delete ('sort')
    next.set (key, value)
-    return next
+    if (key !== 'mode') return next
+    const resolved = normaliseCountsParams (resource, next, definition)
+    const axes = [...readCountsJSON<unknown[]> (resolved, 'rows', []),
+        ...readCountsJSON<unknown[]> (resolved, 'cols', [])]
+    const allowed = value === 'summary'
+        ? ['count', ...axes.map ((_, index) => `a${index}`)]
+        : fieldsForCounts (resource, definition).map (field => field.key)
+    if (readCountSort (resolved.get ('sort')).some (sort => !allowed.includes (sort.key)
+        && !(value === 'summary' && /^measure_[0-9a-f]+$/.test (sort.key))))
+      next.delete ('sort')
+    return normaliseCountsParams (resource, next, definition)
  })
  return <form className="shrink-0" onSubmit={event => {
    event.preventDefault ()
    const next = new URLSearchParams (draft)
    next.delete ('page')
    next.delete ('execution_at')
-    execute (normaliseCountsParams (resource, next))
+    execute (normaliseCountsParams (resource, next, definition))
  }}>
    {!history && <div className="flex flex-wrap items-center gap-2 border-b pb-1
 	dark:border-slate-700">
@@ -2,14 +2,14 @@ import CountsResizeHandle from '@/components/counts/CountsResizeHandle'
 import { useUITranslation } from '@/lib/useUITranslation'


-const CountsRowNumber = ({ value }: { value?: number }) => {
+const CountsRowNumber = ({ value, rowSpan }: { value?: number; rowSpan?: number }) => {
  const { label, message } = useUITranslation ('counts')
  if (value != null) return <td data-counts-copy={String (value)}
      className="border-b px-2 py-1 text-right align-top tabular-nums dark:border-slate-700">
    {value}</td>
-  return <th data-counts-heading={message ('rowNumbers').text} className="relative px-2 py-1">
-    {label ('rowNumbers')}
-    <CountsResizeHandle field="row_number" label={message ('rowNumbers')}/>
+  return <th rowSpan={rowSpan} data-counts-heading={message ('rowNumberHeading').text} className="relative px-2 py-1">
+    {label ('rowNumberHeading')}
+    <CountsResizeHandle field="row_number" label={message ('rowNumberHeading')}/>
  </th>
 }

@@ -110,6 +110,7 @@ const CountsSelectableTable = (
      const table = copyTable ()
      return countsClipboard ({
 	  columns: table.columns.slice (bounds.left, bounds.right + 1),
+	  headerRows: table.headerRows?.map (row => row.slice (bounds.left, bounds.right + 1)),
 	  rows: table.rows.slice (bounds.top, bounds.bottom + 1)
 	      .map (row => row.slice (bounds.left, bounds.right + 1)) }, headers)
    }
@@ -8,12 +8,13 @@ import type { CountSort } from '@/lib/counts'


 const CountsSortHeader = (
-    { field, label, sorts, change, structured = false }: {
+    { field, label, sorts, change, structured = false, rowSpan, colSpan, resizable = true }: {
 	field: string
 	label: { text: string; language: string }
 	sorts: CountSort[]
 	change: (key: string, additive: boolean) => void
-	structured?: boolean },
+	structured?: boolean
+	rowSpan?: number; colSpan?: number; resizable?: boolean },
 ) => {
  const { message } = useUITranslation ('counts')
  const press = useRef<{ x: number; y: number
@@ -36,7 +37,7 @@ const CountsSortHeader = (
      direction: message (`sort.${state}`).text })

  return (
-      <th data-counts-heading={label.text}
+      <th data-counts-heading={label.text} rowSpan={rowSpan} colSpan={colSpan}
 	  className="relative overflow-hidden whitespace-nowrap px-1 py-1"
 	  aria-sort={(sorts.length > 1 && priority >= 0) ? 'other' : state}>
 	<Button type="button" variant="ghost" size="sm"
@@ -89,7 +90,7 @@ const CountsSortHeader = (
 	  {priority >= 0 && <span aria-hidden>
 	    {direction === 'asc' ? '▲' : '▼'}{sorts.length > 1 && priority + 1}</span>}
 	</Button>
-	<CountsResizeHandle field={field} label={label}/>
+	{resizable && <CountsResizeHandle field={field} label={label}/>}
      </th>)
 }

@@ -5,10 +5,11 @@ import CountsSortHeader from '@/components/counts/CountsSortHeader'
 import { changeCountSort, countsRequestParams, readCountSort, writeCountSort } from '@/lib/counts'
 import { countsAxisLabel, countsFieldLabel, readCountsJSON, useCountsDefinition }
    from '@/lib/countsDefinitions'
+import { cn } from '@/lib/utils'
 import { useLocale } from '@/lib/useLocale'
 import { useUITranslation } from '@/lib/useUITranslation'

-import type { CountsResource, CountsResult } from '@/lib/counts'
+import type { CountsPivotHeader, CountsResource, CountsResult } from '@/lib/counts'
 import type { CountsAxis } from '@/lib/countsDefinitions'


@@ -19,25 +20,26 @@ const CountsSummaryResults = (
 ) => {
  const definition = useCountsDefinition ()
  const locale = useLocale ()
-  const { label, message } = useUITranslation ('counts')
-  const rowNumbers = params.get ('row_numbers') === '1'
+  const { message } = useUITranslation ('counts')
+  const numbered = params.get ('row_numbers') === '1'
  const rows = data.rows ?? []
  const cols = data.cols ?? []
-  const axes = [...rows, ...cols]
  const cells = data.cells ?? []
-  const rowKeys = [...new Set (cells.map (cell => JSON.stringify (
-      cell.values.slice (0, rows.length))))]
-  const columnKeys = data.columnValues?.map (values => JSON.stringify (values))
-      ?? [...new Set (cells.map (cell => JSON.stringify (cell.values.slice (rows.length))))]
-  if (cols.length === 0 && columnKeys.length === 0) columnKeys.push ('[]')
+  const rowHeaders: CountsPivotHeader[] = data.rowHeaders ?? [...new Set (
+      cells.map (cell => JSON.stringify (cell.values.slice (0, rows.length))))]
+      .map (key => ({ values: JSON.parse (key), kind: 'data' }))
+  const columnHeaders: CountsPivotHeader[] = data.columnHeaders
+      ?? (data.columnValues ?? [[]]).map (values => ({ values, kind: 'data' }))
  const sorts = readCountSort (params.get ('sort'))
+  const change = (key: string, additive: boolean) => update (
+      'sort', writeCountSort (changeCountSort (sorts, key, additive)))
  const display = (value: string | number | null, axis: CountsAxis, index: number): string => {
    if (value == null) return axis.field === 'user' ? message ('bot').text : ''
    const logical = data.axisLabels?.[`a${index}`]?.[String (value)]
    if (axis.field === 'user') return message ('actorWithId', {
-	name: logical || message ('notRegistered').text, id: value }).text
+        name: logical || message ('notRegistered').text, id: value }).text
    if (logical != null) return logical
-    if (['tags', 'user', 'language_code', 'source_language_code'].includes (axis.field))
+    if (['tags', 'language_code', 'source_language_code'].includes (axis.field))
      return message ('notRegistered').text
    if (axis.field === 'changed_field') return message (countsFieldLabel (String (value))).text
    if (axis.field === 'event_type') return message (`events.${value}`).text
@@ -45,71 +47,140 @@ const CountsSummaryResults = (
      return message (`common:categories.${value}`).text
    return String (value)
  }
-  const drill = (values: (string | number | null)[]) => {
+  const aggregateLabel = (header: CountsPivotHeader) => message (
+      header.kind === 'grand_total' ? 'grandTotal' : 'subtotal').text
+  const leading = Math.max (rows.length, cols.length > 0 ? 1 : 0)
+  const levels = Math.max (1, cols.length)
+  const names = (header: CountsPivotHeader, axes: CountsAxis[], offset: number) =>
+      header.values.map ((value, index) => display (value, axes[index], offset + index))
+  const columnKey = (header: CountsPivotHeader) => `${header.kind}:${JSON.stringify (header.values)}`
+  const measureKey = (header: CountsPivotHeader) => header.values.length === 0 ? 'count'
+      : `measure_${[...new TextEncoder ().encode (JSON.stringify (header.values))]
+          .map (byte => byte.toString (16).padStart (2, '0')).join ('')}`
+  const keys = [...(numbered ? ['row_number'] : []),
+      ...Array.from ({ length: leading }, (_, index) => `a${index}`),
+      ...columnHeaders.map (columnKey)]
+  const full = new Map (cells.map (cell => [JSON.stringify (cell.values), cell.count]))
+  const totals = new Map ((data.pivotTotals ?? []).map (cell => [
+      JSON.stringify ([cell.row, cell.column]), cell.count]))
+  const count = (row: CountsPivotHeader, column: CountsPivotHeader) =>
+      (row.values.length === rows.length && column.values.length === cols.length)
+      ? full.get (JSON.stringify ([...row.values, ...column.values])) ?? 0
+      : totals.get (JSON.stringify ([row.values, column.values])) ?? 0
+  const drill = (row: CountsPivotHeader, column: CountsPivotHeader) => {
    const next = new URLSearchParams (params)
    const existing = readCountsJSON<unknown[]> (params, 'drill', [])
    next.set ('drill', JSON.stringify ([...existing,
-        ...axes.map ((axis, index) => ({ ...axis, value: values[index] }))]))
+        ...row.values.map ((value, index) => ({ ...rows[index], value })),
+        ...column.values.map ((value, index) => ({ ...cols[index], value }))]))
    next.set ('mode', 'details')
    next.delete ('sort')
    next.delete ('page')
    return `/counts/${resource}?${next}`
  }
-  const keys = [...(rowNumbers ? ['row_number'] : []), ...rows.map ((_, index) => `a${index}`),
-      ...columnKeys.map ((_, index) => `cell${index}`)]
+  let ordinal = (data.page - 1) * data.limit
+  const rowLabels = rowHeaders.map (header => {
+    const labels = names (header, rows, 0)
+    const number = header.kind === 'data' ? String (++ordinal) : ''
+    if (header.kind !== 'data') labels.push (aggregateLabel (header))
+    return [...(numbered ? [number] : []),
+        ...Array.from ({ length: leading }, (_, index) => labels[index] ?? '')]
+  })
+  // This unmerged matrix is also the single source for TSV and HTML clipboard headings.
+  const headingRows = Array.from ({ length: levels }, (_, level) => [
+      ...(numbered ? [level === 0 ? message ('rowNumberHeading').text : ''] : []),
+      ...Array.from ({ length: leading }, (_, index) =>
+          level === 0 && rows[index] != null
+          ? countsAxisLabel (rows[index], definition, locale).text : ''),
+      ...columnHeaders.map ((header, index) => {
+        if (cols.length === 0) return header.kind === 'data'
+            ? message ('count').text : aggregateLabel (header)
+        if (level > header.values.length) return ''
+        if (level === header.values.length)
+          return header.kind === 'data' ? '' : aggregateLabel (header)
+        const prefix = header.values.slice (0, level + 1)
+        const previous = columnHeaders[index - 1]
+        if (level < levels - 1 && previous != null
+            && JSON.stringify (previous.values.slice (0, level + 1)) === JSON.stringify (prefix))
+          return ''
+        return display (header.values[level], cols[level], rows.length + level)
+      })])
+  const matrix = rowHeaders.map ((header, index) => [...rowLabels[index],
+      ...columnHeaders.map (column => String (count (header, column)))])
+  const headerCells = (level: number) => {
+    const output = []
+    for (let index = 0; index < columnHeaders.length; ++index)
+    {
+      const header = columnHeaders[index]
+      if (cols.length > 0 && level > header.values.length) continue
+      const aggregate = header.kind !== 'data' && level === header.values.length
+      const leaf = level === levels - 1 || aggregate
+      const text = aggregate ? aggregateLabel (header)
+          : (cols.length === 0 ? message ('count').text
+             : display (header.values[level], cols[level], rows.length + level))
+      let span = 1
+      if (!leaf)
+      {
+        const prefix = JSON.stringify (header.values.slice (0, level + 1))
+        while (index + span < columnHeaders.length)
+        {
+          const sibling = columnHeaders[index + span]
+          if (sibling.values.length <= level
+              || JSON.stringify (sibling.values.slice (0, level + 1)) !== prefix) break
+          ++span
+        }
+      }
+      const sortKey = leaf ? measureKey (header) : `a${rows.length + level}`
+      const field = leaf ? columnKey (header) : sortKey
+      output.push (<CountsSortHeader key={`${level}:${field}:${index}`} field={field}
+          colSpan={span} rowSpan={aggregate ? levels - level : 1} resizable={leaf}
+          label={{ text, language: message ('count').language }}
+          sorts={sorts.map (sort => sort.key === sortKey ? { ...sort, key: field } : sort)}
+          change={(_, additive) => change (sortKey, additive)}/>)
+      index += span - 1
+    }
+    return output
+  }
  return <div className="min-h-0 flex-1 overflow-auto" data-counts-results aria-busy={pending}>
    <CountsSelectableTable family={`pivot_${resource}`} columns={keys}
-        identity={`${countsRequestParams (params)}:${keys}`} className="text-left text-sm">
-      <thead className="sticky top-0 z-20"><tr>
-	{rowNumbers && <CountsRowNumber/>}
-        {rows.map ((axis, index) => <CountsSortHeader key={axis.field} field={`a${index}`}
-	    label={countsAxisLabel (axis, definition, locale)} sorts={sorts}
-            change={(key, additive) => update ('sort', writeCountSort (
-                changeCountSort (sorts, key, additive)))}/>)}
-        {columnKeys.map ((key, index) => {
-          const values = JSON.parse (key) as (string | number | null)[]
-          const name = values.map ((value, position) =>
-	      `${countsAxisLabel (cols[position], definition, locale).text}: ${
-                  display (value, cols[position], rows.length + position)}`).join (' / ')
-          const sortKey = cols.length === 0 ? 'count' : `measure_${[
-              ...new TextEncoder ().encode (key)].map (byte =>
-                  byte.toString (16).padStart (2, '0')).join ('')}`
-          return <CountsSortHeader key={key} field={`cell${index}`}
-	      label={{ text: name || message ('count').text,
-		  language: message ('count').language }}
-              sorts={sorts.map (sort => sort.key === sortKey
-                  ? { ...sort, key: `cell${index}` } : sort)}
-              change={(_, additive) => update ('sort', writeCountSort (
-                  changeCountSort (sorts, sortKey, additive)))}/>
-        })}
-      </tr></thead>
-      <tbody>{rowKeys.map ((rowKey, rowIndex) => {
-        const rowValues = JSON.parse (rowKey) as (string | number | null)[]
-        return <tr key={rowKey}>
-	  {rowNumbers && <CountsRowNumber value={(data.page - 1) * data.limit + rowIndex + 1}/>}
-          {rowValues.map ((value, index) => <td key={index}
-              className="overflow-hidden break-words border px-2 py-1 dark:border-slate-700"
-	      data-counts-copy={display (value, rows[index], index)}
-	      lang={(value == null && rows[index].field === 'user')
-		  ? message ('bot').language : (rows[index].field === 'event_type'
-		      ? message (`events.${value}`).language : undefined)}>
-            {display (value, rows[index], index)}</td>)}
-          {columnKeys.map (columnKey => {
-            const columnValues = JSON.parse (columnKey) as (string | number | null)[]
-            const values = [...rowValues, ...columnValues]
-	    const cell = cells.find (cell => JSON.stringify (
-		cell.values) === JSON.stringify (values))
-            return <td key={columnKey} data-counts-copy={String (cell?.count ?? 0)}
-                className="border px-2 py-1 dark:border-slate-700">
-              <PrefetchLink to={drill (values)}>{cell?.count ?? 0}</PrefetchLink>
-            </td>
-          })}
-        </tr>
-      })}</tbody>
+        copyTable={() => ({ columns: keys.map ((_, index) => ({ label: headingRows[0][index] })),
+            headerRows: headingRows, rows: matrix })}
+        identity={`${countsRequestParams (params)}:${JSON.stringify (keys)}`}
+        className="text-left text-sm">
+      <thead className="sticky top-0 z-20">
+        {headingRows.map ((_, level) => <tr key={level}>
+          {level === 0 && <>
+            {numbered && <CountsRowNumber rowSpan={levels}/>}
+            {Array.from ({ length: leading }, (_, index) => rows[index] == null
+                ? <th key={index} rowSpan={levels}/>
+                : <CountsSortHeader key={rows[index].field} field={`a${index}`}
+                    rowSpan={levels} label={countsAxisLabel (rows[index], definition, locale)}
+                    sorts={sorts} change={change}/>)}
+          </>}
+          {headerCells (level)}
+        </tr>)}
+      </thead>
+      <tbody>{rowHeaders.map ((row, index) => <tr key={columnKey (row)}>
+        {rowLabels[index].map ((value, offset) => <td key={offset} data-counts-copy={value}
+            data-counts-aggregate={row.kind !== 'data' ? '' : undefined}
+            className={cn ('overflow-hidden break-words border px-2 py-1 dark:border-slate-700',
+                row.kind !== 'data' && 'bg-slate-200 text-slate-950 font-semibold',
+                row.kind !== 'data' && 'dark:bg-slate-700 dark:text-slate-50',
+                numbered && offset === 0 && 'text-right tabular-nums')}>{value}</td>)}
+        {columnHeaders.map (column => <td key={columnKey (column)}
+            data-counts-copy={String (count (row, column))}
+            data-counts-aggregate={(row.kind !== 'data' || column.kind !== 'data')
+                ? '' : undefined}
+            className={cn ('border px-2 py-1 dark:border-slate-700',
+                (row.kind !== 'data' || column.kind !== 'data')
+                && 'bg-slate-200 text-slate-950 font-semibold',
+                (row.kind !== 'data' || column.kind !== 'data')
+                && 'dark:bg-slate-700 dark:text-slate-50')}>
+          <PrefetchLink to={drill (row, column)}>{count (row, column)}</PrefetchLink>
+        </td>)}
+      </tr>)}</tbody>
    </CountsSelectableTable>
-    {cells.length === 0 && <p>{label ('empty')}</p>}
  </div>
 }

-
 export default CountsSummaryResults
@@ -18,6 +18,17 @@
  @apply bg-slate-900 text-slate-100;
 }

+.counts-grid > tbody > tr > td[data-counts-aggregate]:not([data-counts-selected]) {
+  background-color: #e2e8f0;
+  color: #0f172a;
+  font-weight: 600;
+}
+
+.dark .counts-grid > tbody > tr > td[data-counts-aggregate]:not([data-counts-selected]) {
+  background-color: #334155;
+  color: #f8fafc;
+}
+
 .counts-grid > thead {
  @apply bg-slate-200 text-slate-950;
 }
@@ -1,7 +1,7 @@
-import { countsFieldLabel } from '@/lib/countsDefinitions'
+import { countsFieldLabel, readCountsJSON } from '@/lib/countsDefinitions'
 import { apiDownload, apiGet } from '@/lib/api'

-import type { CountsDefinition } from '@/lib/countsDefinitions'
+import type { CountsAxis, CountsDefinition } from '@/lib/countsDefinitions'
 import type { LocaleCode } from '@/lib/locales'
 import type { TagNameSnapshot } from '@/types'

@@ -55,7 +55,13 @@ export type CountsStateTotals = {
    assignments: number | null
    deprecatedTags: number | null
    externalAssignments: number | null }
+export type CountsPivotHeader = { values: (string | number | null)[]
+    kind: 'data' | 'subtotal' | 'grand_total' }
 export type CountsResult = {
+    rowHeaders?: CountsPivotHeader[]
+    columnHeaders?: CountsPivotHeader[]
+    pivotTotals?: { row: (string | number | null)[]; column: (string | number | null)[]
+        count: number }[]
    executionAt?: string
    columnValues?: (string | number | null)[][]
    cells?: { values: (string | number | null)[]; count: number }[]
@@ -83,11 +89,10 @@ export type CountRecord = Record<string, unknown>
 export const countColumns: Record<string, string> = {
    event_type: 'counts:eventType',
    thumbnail: 'counts:columns.thumbnailDisplay', resource_id: 'counts:columns.resourceId',
-    version_no: 'history:version', is_latest: 'counts:columns.latest',
+    version_no: 'counts:columns.version', is_latest: 'counts:columns.latest',
    title: 'counts:columns.postTitle', url: 'counts:columns.postURL',
    thumbnail_base: 'counts:columns.thumbnailURL', tags: 'counts:columns.tags',
    parents: 'shared:labels.parentPosts', video_ms: 'shared:labels.duration',
-    original_created_at: 'shared:labels.originalCreatedAt',
    original_created_from: 'counts:columns.originalFrom',
    original_created_before: 'counts:columns.originalBefore',
    name: 'history:tagName', names: 'counts:columns.names',
@@ -144,7 +149,7 @@ export const columnsForCounts = (
    'resource_id', 'version_no', 'is_latest',
    ...(resource === 'posts'
        ? ['title', 'url', 'thumbnail_base', 'tags', 'parents', 'video_ms',
-           'original_created_at', 'original_created_from', 'original_created_before']
+           'original_created_from', 'original_created_before']
        : (resource === 'tags'
           ? ['name', 'names', 'category', 'aliases', 'parents', 'deprecated']
 	   : (definition?.fields.filter (field => ![
@@ -206,6 +211,7 @@ export const selectedCountColumns = (
    params: URLSearchParams,
    definition?: CountsDefinition,
 ): CountColumn[] => {
+  const resolved = normaliseCountsParams (resource, params, definition)
  const common = ['resource_id', 'version_no', 'event_type', 'user', 'created_at']
  const defaults: Record<CountsResource, string[]> = {
      posts: ['title', 'url', 'tags', 'parents', 'video_ms'],
@@ -214,9 +220,9 @@ export const selectedCountColumns = (
      tag_descriptions: ['language_code', 'body', 'source_language_code'],
      tag_groups: ['name', 'description', 'members'],
      materials: ['url', 'source_kind', 'tag_id'] }
-  const selected = params.has ('columns') ? params.get ('columns')!.split (',')
+  const selected = resolved.has ('columns') ? resolved.get ('columns')!.split (',')
      : [...common, ...defaults[resource]]
-  return orderedCountFields (fieldsForCounts (resource, definition), params)
+  return orderedCountFields (fieldsForCounts (resource, definition), resolved)
      .map (field => field.key as CountColumn).filter (key => selected.includes (key))
 }

@@ -281,6 +287,7 @@ export const defaultCountsMode = (definition: string | null): 'summary' | 'detai
 export const normaliseCountsParams = (
    resource: CountsResource,
    source: URLSearchParams,
+    definition?: CountsDefinition,
 ): URLSearchParams => {
  const params = new URLSearchParams (source)
  if (!params.has ('definition'))
@@ -306,6 +313,27 @@ export const normaliseCountsParams = (
    params.set ('columns', columnsForCounts (resource).filter (key => selected.has (key))
 	.join (','))
  }
+  if (params.has ('sort'))
+    params.set ('sort', params.get ('sort')!.split (',')
+        .filter (entry => entry.split (':')[0] !== 'original_created_at').join (','))
+  if (params.has ('order'))
+    params.set ('order', params.get ('order')!.split (',')
+        .filter (key => key !== 'original_created_at').join (','))
+  const defaults = definition?.defaults?.find (entry =>
+      entry.definition === params.get ('definition') && entry.mode === params.get ('mode'))
+  for (const { key, value } of defaults?.params ?? [])
+  {
+    if (params.has (key)) continue
+    if (key === 'sort')
+    {
+      const expected = defaults?.params.find (entry => entry.key === 'rows')?.value
+      const axes = readCountsJSON<CountsAxis[]> (params, 'rows', [])
+      const first = expected == null ? null : (JSON.parse (expected) as CountsAxis[])[0]
+      if (!Array.isArray (axes) || axes[0]?.field !== first?.field
+          || (axes[0]?.grain ?? 'month') !== (first?.grain ?? 'month')) continue
+    }
+    params.set (key, value)
+  }
  return params
 }

@@ -2,7 +2,7 @@ export type CountsClipboard = { text: string; html: string }
 export type CountsClipboardColumn = { label: string; children?: CountsClipboardColumn[] }
 export type CountsClipboardCell = string | CountsClipboardTable
 export type CountsClipboardTable = {
-    columns: CountsClipboardColumn[]; rows: CountsClipboardCell[][] }
+    columns: CountsClipboardColumn[]; rows: CountsClipboardCell[][]; headerRows?: string[][] }


 const escapeHTML = (value: string): string => value.replace (/[&<>"']/g, character =>
@@ -59,7 +59,8 @@ export const countsClipboard = (
    source: string[][] | CountsClipboardTable,
    headers = false,
 ): CountsClipboard => {
-  const headings = !Array.isArray (source) && headers ? headerRows (source.columns) : []
+  const headings = (!Array.isArray (source) && headers)
+      ? source.headerRows ?? headerRows (source.columns) : []
  const rows = Array.isArray (source) ? source : [...headings, ...dataRows (source)]
  const headingCount = Array.isArray (source) ? (headers ? 1 : 0) : headings.length
  // Excel accepts quoted TSV fields only when delimiters or quotes require them.
@@ -17,6 +17,7 @@ export type CountsFieldMetadata = {
    key: string; type: CountsFieldType; nullable: boolean; operators: string[] }
 export type CountsDefinition = {
    fields: CountsFieldMetadata[]
+    defaults?: { definition: string; mode: string; params: { key: string; value: string }[] }[]
    axes: { latest: string[]; history: string[] }
    grains: string[] }

@@ -42,7 +43,7 @@ export const countsFilterFields = (

 export const countsFieldLabel = (key: string): string => {
  const labels: Record<string, string> = {
-      resource_id: 'columns.resourceId', version_no: 'history:version',
+      resource_id: 'columns.resourceId', version_no: 'columns.version',
      user: 'history:actor', created_at: 'columns.changedAt', name: 'history:name',
      title: 'columns.postTitle', url: 'columns.postURL', thumbnail_base: 'columns.thumbnailURL',
      tags: 'columns.tags', tags_json: 'columns.tags', names: 'columns.names',
@@ -62,11 +63,10 @@ export const countsAxisLabel = (
    locale: LocaleCode,
 ): { text: string; language: string } => {
  const field = translateUIMessage (countsFieldLabel (axis.field), 'counts', locale)
-  if (axis.grain == null || definition.fields.find (item => item.key === axis.field)
-      ?.type !== 'datetime') return field
+  if (definition.fields.find (item => item.key === axis.field)?.type !== 'datetime') return field
  return translateUIMessage ('axisWithGrain', 'counts', locale, {
      field: field.text,
-      grain: translateUIMessage (`grains.${axis.grain}`, 'counts', locale).text })
+      grain: translateUIMessage (`grains.${axis.grain ?? 'month'}`, 'counts', locale).text })
 }


@@ -2,7 +2,7 @@ import { fieldsForCounts, orderedCountFields, selectedCountChildren,
 	 sortedCountChildren } from '@/lib/counts'
 import { countsEventTypes } from '@/lib/countsDefinitions'
 import { translateUIMessage } from '@/lib/i18n'
-import { localisedDateString, msToTime, originalCreatedAtString } from '@/lib/utils'
+import { localisedDateString, msToTime } from '@/lib/utils'

 import type { CountColumn, CountField, CountRecord,
 	      CountsResource, CountsVersion } from '@/lib/counts'
@@ -34,13 +34,6 @@ export const countsCellText = (
  case 'category':
    return translateUIMessage (`common:categories.${row.category}`, 'counts', locale).text
  case 'video_ms': return row.videoMs == null ? '' : msToTime (row.videoMs)
-  case 'original_created_at':
-    if (timezone !== 'Asia/Tokyo')
-      return translateUIMessage ('sections.range', 'counts', locale, {
-          begin: row.originalCreatedFrom == null ? '' : date (row.originalCreatedFrom),
-          end: row.originalCreatedBefore == null ? '' : date (row.originalCreatedBefore) }).text
-    return originalCreatedAtString (
-	row.originalCreatedFrom ?? null, row.originalCreatedBefore ?? null, locale)
  case 'original_created_from':
  case 'original_created_before':
    {
@@ -314,6 +307,8 @@ export const countsExportLabels = (
  labels.name = translateUIMessage ('history:name', 'counts', locale).text
  for (const event of countsEventTypes)
    labels[`event_type:${event}`] = translateUIMessage (`events.${event}`, 'counts', locale).text
+  labels.subtotal = translateUIMessage ('subtotal', 'counts', locale).text
+  labels.grandTotal = translateUIMessage ('grandTotal', 'counts', locale).text
  labels.bot = translateUIMessage ('bot', 'counts', locale).text
  labels.actorFormat = translateUIMessage ('actorWithId', 'counts', locale, {
      name: '{{name}}', id: '{{id}}' }).text
@@ -376,7 +371,7 @@ export const countsDetailClipboardTable = (
 	  ? undefined : clipboardColumns (
 	  field.children, field.key, params, locale) }))
  if (rowStart != null)
-    columns.unshift ({ label: translateUIMessage ('rowNumbers', 'counts', locale).text,
+    columns.unshift ({ label: translateUIMessage ('rowNumberHeading', 'counts', locale).text,
 	children: undefined })
  return { columns, rows: rows.map ((row, index) => {
    const cells: CountsClipboardCell[] = fields.map (field => field.children == null
@@ -6,7 +6,7 @@ export const MAX_COUNT_WIDTH = 2000
 export const defaultCountWidths: Record<string, number> = {
    row_number: 72, thumbnail: 88, resource_id: 88, version_no: 88, is_latest: 104,
    title: 300, url: 300, thumbnail_base: 300, tags: 560, parents: 180,
-    video_ms: 120, original_created_at: 260, original_created_from: 240,
+    video_ms: 120, original_created_from: 240,
    original_created_before: 240, name: 240, names: 480, category: 180,
    aliases: 360, deprecated: 240, user: 200, created_at: 240, group: 240, count: 160,
    period: 200, tag_id: 88, id: 88, versionNo: 88, kind: 140, sections: 260,
@@ -42,10 +42,11 @@
  "empty": "該当する履歴はありません。",
  "columns": {
    "changedAt": "操作日時",
+    "version": "版",
    "resourceId": "Id.",
-    "postTitle": "投稿タイトル",
-    "postURL": "投稿 URL",
-    "tags": "記載タグ",
+    "postTitle": "タイトル",
+    "postURL": "URL",
+    "tags": "タグ",
    "deprecated": "廃止状態",
    "latest": "最新フラグ",
    "thumbnailURL": "サムネール元 URL",
@@ -232,6 +233,9 @@
    "profile": "出力設定",
    "path": "出力パス"
  },
+  "rowNumberHeading": "No.",
+  "subtotal": "小計",
+  "grandTotal": "綜合計",
  "rowNumbers": "行番号",
  "periodSeparator": "〜",
  "bot": "$t(history:bot)",
@@ -37,7 +37,7 @@ import type { CountsResource } from '@/lib/counts'
 const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
  const definition = useCountsDefinition ()
  const [source, setParams] = useSearchParams ()
-  const params = normaliseCountsParams (resource, source)
+  const params = normaliseCountsParams (resource, source, definition)
  const canonical = params.toString ()
  const controlParams = new URLSearchParams (params)
  controlParams.delete ('nested_json')