Question

我有三种模式:地点和特区;热点和特区;账户。

在我的工作地点模式中,我有:

has_many :hotspots
has_many :accounts, :foreign_key => :calledstationidclean, :through => :hotspots

我试图从每个地点账户模式中显示一些概要数据。

The following work ok:

  scope :location_history, lambda { |id|
                               joins( INNER JOIN hotspots b ON locations.id = b.location_id INNER JOIN account ON b.mac = account.calledstationidclean )
                               .where(:id => id)
                               .select("count(locations.id) AS sessions_count, sum(account.acctoutputoctets) AS downloads, sum(account.acctinputoctets) AS uploads, count(distinct account.callingstationid) AS unique_user")
                            }

但我需要作一些计算,我可以说明如何这样做。

通常,在账户模式Im中,能够做这样的事情:

 def self.session_time
   Account.sum("acctsessiontime")
 end

 def self.average_session
   self.session_time / Account.count
 end

我怎么能做类似的事情,但在我的所在地模式中——并且只为特定地点“一米观察”展示信息? 我是否确实需要参加?

Answer 1

是的,你必须加入。

  scope :location_history,
        lambda { |id| joins(:hotspots, :accounts).where(:id => id).
                      select("sum(account.acctsessiontime) as acctsessiontime, count(locations.id) AS sessions_count, sum(account.acctoutputoctets) AS downloads, sum(account.acctinputoctets) AS uploads, count(distinct account.callingstationid) AS unique_user")
               }

这样,你就可以使用一个小组,把所有这些记录与地点的记录结合起来。

  scope :with_history,
        lambda { |id| joins(:hotspots, :accounts).where(:id => id).
                      select("locations.*, sum(account.acctsessiontime) as acctsessiontime, count(locations.id) AS sessions_count, sum(account.acctoutputoctets) AS downloads, sum(account.acctinputoctets) AS uploads, count(distinct account.callingstationid) AS unique_user")
               }

这将把位置物体归还所有地点,并将把座标汇回。

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