ruby-on-rails - 我如何使用事件记录从 foren 表中进行选择

Question

我有 2 个表，帐户和订阅。所有帐户都有订阅，当我订阅时

Account.last.subscription.name
  Account Load (0.4ms)  SELECT "accounts".* FROM "accounts" ORDER BY "accounts"."id" DESC LIMIT 1
  Subscription Load (0.2ms)  SELECT "subscriptions".* FROM "subscriptions" WHERE "subscriptions"."account_id" = 73 LIMIT 1
"free"

但我正在尝试获取所有设置为免费的帐户。

Answer 1

您的问题没有提供详细信息，因此我们必须做出一些假设。假设 Subscription 有一个 bool 值 free 列。

# Rails 4
Account.joins(:subscriptions).where(free: true).references(:subscriptions)

# Rails 3
Account.joins(:subscriptions).where('subscriptions.free = ?', true)

如果我们假设 free 是一个帐户属性:

Account.where(free: true)

如果您想提取订阅详细信息:

Account.where(free: true).includes(:subscriptions)