ruby-on-rails - 如何使用活动记录从 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，我什么时候订阅

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"

但我试图让所有设置为免费的帐户。

Answer 1

您的问题中的细节很少，因此我们必须做出一些假设。假设Subscription有一个布尔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 Account 属性：

Account.where(free: true)

如果您想提取订阅详细信息：

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