Question

如果我有一个名为User的模型has_many :games和游戏has_many :events - 如何让所有没有任何游戏的用户或任何有暂停事件的游戏。

以下是我的尝试：

示例：

用户类：

scope :with_no_games -> {
  joins("LEFT OUTER JOIN games g on g.user_id = users.id").where("games.id IS NULL")
}  

scope :with_suspended_games_or_no_games -> {
  with_no_games.merge(Game.suspended) # <- this doesn't work
}

游戏课程：

scope :suspended -> {
  joins("INNER JOIN events e ON event.game_id = games.id AND event.name = 'suspended'")
}

如果我运行User.with_suspended_games_or_no_games，我会得到以下SQL语句：

SELECT \"users\".* FROM \"users\" LEFT OUTER JOIN games ON games.user_id = users.id INNER JOIN events ON events.game_id = games.id AND events.name = 'suspended' WHERE (games.user_id IS NULL)"

这不是我要找的。我错过了什么？

Answer 1

我认为你在寻找

scope :with_suspended_games_or_no_games -> {
  with_no_games.joins(:games).merge(Game.suspended)
}

看到sql尝试从rails控制台运行以下命令：

User.with_suspended_games_or_no_games.to_sql

<强>奖金

你也可以写下你的范围：

用户

scope :with_no_games -> { joins(:games).where(games: {id: nil}) } scope :with_suspended_games_or_no_games -> { joins(:games).with_no_games.merge(Game.suspended) }

<强>游戏

scope :suspended -> { joins(:events).where(events: {name: 'suspended'}) }

使用关联的模型范围

1 个答案: