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 Card::Error::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 Card::Error::BadQuery, "count with item: #{item} not yet implemented"
  end
end