はてなブックマーク

OR scope :tagged_any, ->(tags) { where( id: Tagging .select(:question_id) .where(tag_id: tags) .build_arel ) } AND scope :tagged_all, ->(tags) { tags.inject(self) {|scope, tag| scope.where( id: Tagging .select(:question_id) .where(tag_id: tag) .build_arel ) } } SELECT "questions".* FROM "questions" WHERE "questions"."id" IN (SELECT question_id FROM "taggings" WHERE "taggings"."tag_id" = 1) AND "qu