Question

我有3个模型：member，team和team_enrollment。结构如下：

class Member < ApplicationRecord
  has_many :team_enrollments    
  has_many :teams, -> {order 'team_enrollments.termination_date DESC NULLS LAST'}, through: :team_enrollments
end

class TeamEnrollment < ApplicationRecord
  belongs_to :team
  belongs_to :member
end

class Team < ApplicationRecord
    has_many :team_enrollments
    has_many :members, through: :team_enrollments
end

我正在努力做到这一点，当有人从一个成员调用一个团队（所以Member.first.teams）时，团队按照{{1}上存在的属性termination_date按降序排序表。我也想要它，如果team_enrollments为零，那么它就在订单的最后。我认为上面的termination_date行可行，但事实并非如此。它似乎对订单没有影响。我该怎么改变呢？

顺便说一句，我在本地和生产中使用postgres。

Answer 1

我会尝试使用default_scope而不是尝试将order子句放在关联

中

class Member < ApplicationRecord
  has_many :team_enrollments    
  has_many :teams, through: :team_enrollments
end

class TeamEnrollment < ApplicationRecord
  belongs_to :team
  belongs_to :member
  default_scope {order 'termination_date DESC NULLS LAST'}
end

class Team < ApplicationRecord
   has_many :team_enrollments
   has_many :members, through: :team_enrollments
end

如何通过特定字段对has_many进行排序

1 个答案: