module Card::Query::CardQuery::Sorting
handle relational (not simple) CQL sort values (see interpret_as_modifier? and order_directives)
sorting with subqueries is not fully supported; only a few experimental examples have been attempted, and even for those the syntax is likely to change.
Generally speaking, sorting subqueries will require a JOIN strategy (as opposed to the “WHERE EXISTS” strategy that is central to queries’ main conditions.)
Constants
- SORT_BY_ITEM_JOIN_MAP
Public Instance Methods
Source
# File lib/card/query/card_query/sorting.rb, line 82 def count_sort_query Query.new return: "coalesce(count(*), 0) as count", group: "sort_join_field", superquery: self end
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# File lib/card/query/card_query/sorting.rb, line 78 def count_subselect val Query.new val.merge(return: "id", superquery: self) end
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# File lib/card/query/card_query/sorting.rb, line 88 def join_cards val, opts={} conditions_on_join = opts.delete :conditions_on_join s = subquery join_opts = { from: self, to: s }.merge opts card_join = Join.new join_opts joins << card_join unless opts[:from].is_a? Join s.conditions_on_join = card_join if conditions_on_join s.interpret val s end
Source
# File lib/card/query/card_query/sorting.rb, line 69 def join_count_sort_query sort_query sort_query.mods[:sort_join_field] = "#{sort_query.table_alias}.id as sort_join_field" # FIXME: HACK! joins << Join.new(from: self, side: "LEFT", to: [sort_query, "srtbl", "sort_join_field"]) end
Source
# File lib/card/query/card_query/sorting.rb, line 17 def sort val return nil unless full? # eg, no sorting on simple count queries interpret_sort_hash val do |value, item, sort_field| sort_by value, item, sort_field end end
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# File lib/card/query/card_query/sorting.rb, line 25 def sort_by val, item, sort_field if sort_field == "count" sort_by_count val, item else sort_by_item_join val, item, sort_field end end
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# File lib/card/query/card_query/sorting.rb, line 48 def sort_by_count val, item method_name = "sort_by_count_#{item}" sort_method_not_implemented :count, item unless respond_to? method_name send method_name, val end
EXPERIMENTAL! sort_by
: { referred_to_by { right: “*follow” }, return count }
Source
# File lib/card/query/card_query/sorting.rb, line 58 def sort_by_count_referred_to val @mods[:sort_by] = "coalesce(count,0)" # needed for postgres sort_query = count_sort_query sort_query.add_condition "referer_id in (#{count_subselect(val).sql})" # FIXME: - SQL generated before SQL phase sort_query.joins << Join.new(from: sort_query, side: "LEFT", to: %w[card_references wr referee_id]) join_count_sort_query sort_query end
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# File lib/card/query/card_query/sorting.rb, line 33 def sort_by_item_join val, item, sort_field join_field = sort_by_item_join_field item join = join_cards val, to_field: join_field, side: "LEFT", conditions_on_join: true @mods[:sort_by] ||= "#{join.table_alias}.#{sort_field}" end
Source
# File lib/card/query/card_query/sorting.rb, line 41 def sort_by_item_join_field item SORT_BY_ITEM_JOIN_MAP[item.to_sym] || sort_method_not_implemented(:join, item) end
Source
# File lib/card/query/card_query/sorting.rb, line 54 def sort_method_not_implemented method, item raise Card::Error::BadQuery, "sorting by ##{method}/#{item} not yet implemented" end
Private Instance Methods
Source
# File lib/card/query/card_query/sorting.rb, line 101 def interpret_sort_hash val val = val.symbolize_keys item = val.delete(:item) || "left" sort_field = val[:return] || "db_content" yield val, item, sort_field end