根据关联模型中的值对记录进行排序

Question

我有两种模式：学校和地址。

Address
    has_many :schools

School
    belongs_to :address

    t.bigint "address_id"

现在我需要在学校模型中建立范围，以便根据地址表中城市的出现情况对学校进行排序。所以我需要以下结果：

School_1 | City_most_popular
School_2 | City_most_popular
School_3 | City_most_popular
School_4 | City_most_popular
School_5 | City_quite_popular
School_6 | City_quite_popular
School_7 | City_not_popular

我写道：School.joins（：地址）.group（＆＃34; schools.id，addresses.city＆＃34;）。order（＆＃34; addresses.city ASC＆＃34;）但这只是允许按城市分组记录并忽略出现。

Answer 1

School
 .joins(:address)
 .select('schools.*, count(*) OVER (PARTITION BY addresses.city) AS count')
 .order('count DESC')