我有一个具有以下模型的 Rails 5 应用程序：
User.rb, Campaign.rb,UserCampaign.rb
关系是User has many Campaigns through UserCampaign。通过这种关系，我可以查询@user.campaigns以查找与该用户相关的所有活动。到现在为止还挺好。
UserCampaign 架构如下所示：
create_table "user_campaigns", force: :cascade do |t|
t.bigint "campaign_id"
t.bigint "user_id"
t.boolean "responded", default: false
t.index ["campaign_id"], name: "index_user_campaigns_on_campaign_id"
t.index ["user_id", "campaign_id"], name: "index_user_campaigns_on_user_id_and_campaign_id"
t.index ["user_id"], name: "index_user_campaigns_on_user_id"
end
理想情况下，我想写@user.campaigns.where(responded: false). 但是，我收到以下错误：
PG::UndefinedColumn: ERROR: column campaigns.responded does not exist LINE 1: ...izard_id" WHERE "user_campaigns"."user_id" = $1 AND "campaigns".... ^ : SELECT "campaigns".* FROM "campaigns" INNER JOIN "user_campaigns" ON "campaigns"."id" = "user_campaigns"."campaign_id" WHERE "user_campaigns"."user_id" = $1 AND "campaigns"."responded" = $2
我知道我得到这个是因为responded它是关于 UserCampaign 而不是 Campaign 的专栏。进行连接以包含响应列的最佳方法是什么？
PG::UndefinedColumn: 错误：列活动。响应不存在
你应该像下面这样重写你的查询
@user.campaigns.joins(:user_campaigns).where(user_campaigns: {responded: false})
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