PostgreSQL的Rails无法按值对记录进行排序，获取PG :: InvalidColumnReference：错误

Question

我有一个名为“候选”的模型，“状态”列为字符串。我想按状态从“新”到“待定”对记录进行排序。我的代码在Sqlite3中可用，但在PostgreSQL中不可用。

这是我的模特

class Candidate < ApplicationRecord
  belongs_to :collaborator, optional: true
  has_many :curriculum_vitaes, dependent: :destroy

  def self.order_by_status
    order_by = ["CASE"]
    STATUS.each_with_index do |status, index|
      order_by << "WHEN status='#{status}' THEN #{index}"
    end
    order_by << "END ASC, name ASC"
    order(order_by.join(" "))
  end

  STATUS = [
    "New",
    "Received CV",
    "Checking CV",
    "Waiting Interview",
    "Waiting Result",
    "Passed",
    "Failed",
    "Pending"
  ]

在控制器中，当我通过 @candidates = Candidate.order_by_status 我总是会出错： PG::InvalidColumnReference: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list

你能帮我吗？