Module: Card::Query::Sorting

Included in:
Card::Query
Defined in:
lib/card/query/sorting.rb

Constant Summary collapse

SORT_JOIN_TO_ITEM_MAP = 
{ left: 'left_id', right: 'right_id' }.freeze

Instance Method Summary collapse

Instance Method Details

#sort(val) ⇒ Object 



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# File 'lib/card/query/sorting.rb', line 6

def sort val
  return nil if @superquery
  sort_field = val[:return] || 'db_content'
  item = val.delete(:item) || 'left'

  if sort_field == 'count'
    sort_by_count val, item
  elsif (join_field = SORT_JOIN_TO_ITEM_MAP[item.to_sym])
    sq = join_cards(val, to_field: join_field,
                         side: 'LEFT',
                         conditions_on_join: true)
    @mods[:sort] ||= "#{sq.table_alias}.#{sort_field}"
  else
    raise BadQuery, "sort item: #{item} not yet implemented"
  end
end

#sort_by_count(val, item) ⇒ Object

EXPERIMENTAL!



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# File 'lib/card/query/sorting.rb', line 24

def sort_by_count val, item
  if item == 'referred_to'
    @mods[:sort] = 'coalesce(count,0)' # needed for postgres
    cs = Query.new(
      return: 'coalesce(count(*), 0) as count',
      group: 'sort_join_field',
      superquery: self
    )
    subselect = Query.new val.merge(return: 'id', superquery: self)
    cs.add_condition "referer_id in (#{subselect.sql})"
    # FIXME: - SQL generated before SQL phase
    cs.joins << Join.new(
      from: cs,
      to: %w(card_references wr referee_id)
    )
    cs.mods[:sort_join_field] = "#{cs.table_alias}.id as sort_join_field"
    # HACK!

    joins << Join.new(
      from: self,
      to: [cs, 'srtbl', 'sort_join_field']
    )
  else
    raise BadQuery, "count with item: #{item} not yet implemented"
  end
end