活动记录插入

我试图让我的Rails应用程序在创建关系方面有一些高级function。 我正在运行MySQL作为后端。 下面的查询在PHPMyAdmin中运行得很好，但是在rails中尝试执行时，它什么都不做，没有错误，没有数据库写入….

我使用活动记录来创建Campaign和Location之间的关系，然后下面的查询应该在campaign_metros表中构建：

class CampaignLocation < ActiveRecord::Base belongs_to :campaign belongs_to :location after_touch :create_campaign_metro private def create_campaign_metro @sql_insert="INSERT INTO `campaign_metros` (`campaign_id`,`metro_id`, `created_at`,`updated_at`) SELECT f.`campaign_id`, f.`city_id`, NOW(), NOW() FROM (SELECT d.`campaign_id`, d.`city_id` FROM (SELECT c.`campaign_id`, c.`city_id` FROM (SELECT distinct a.`campaign_id`, b.`city_id` FROM `campaign_locations` a INNER JOIN `locations` b ON a.`location_id` = b.`id`) c) d LEFT JOIN `campaign_metros` e ON e.`campaign_id` = d.`campaign_id` and e.`metro_id` = d.`city_id` WHERE e.`metro_id` is null and e.`campaign_id` is null) f;" ActiveRecord::Base.connection.execute(@sql_insert) end end 

我从MySQL DELETE FROM中了解子查询作为条件 ，在CodeReaper的第二个答案中，MySQL在处理子查询时需要另一级别的别名，但在Rails中运行我的查询什么都不做。

我怎样才能让它发挥作用？