根據關聯模型中的值對記錄進行排序

Question

我有兩個模型：學校和地址。

Address
    has_many :schools

School
    belongs_to :address

    t.bigint "address_id"

現在，我需要在School模型中建立作用域，以根據地址表中城市的出現情況對學校進行排序。 所以我需要以下結果：

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

我是這樣寫的：School.joins（：address）.group（“ schools.id，addresss.city”）。order（“ addresses.city ASC”），但這僅允許按城市對記錄進行分組，而忽略發生。

Answer 1

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