Rails 5: ActiveRecord 查询加入的最后一个对象 table with OR condition

Question

我需要一些帮助来查询这里 (Rails 5.1)。我有一个名为 Verification (belongs_to :verifiable, polymorphic: true) 的多态关联对象。其他对象，如 Comment，可以有 verifications (has_many :verifications, as: :verifiable)，最后一个（按 id 排序）被认为是当前的。 Verification 有一个枚举属性 status。我需要检索具有特定 user_id（当前用户之一）或 current（即最后一个）状态正确的验证对象（例如，approved).

所以，我正在尝试：

self.where(user_id: user.id).or(self.joins(:verifications).limit(1).where(verifications: { status: 'approved' }))

但是 Rails 给我以下错误：

Relation passed to #or must be structurally compatible. Incompatible values: [:joins, :references, :limit]

我该怎么办？

Answer 1

我无法让它在一个查询中工作（我的 Arel 尝试失败了）。所以希望以下内容就足够了（测试工作）：

latest_verification_ids = Verification.group(:verifiable_id).maximum(:id).values

# SELECT MAX("verifications"."id") AS maximum_id, "verifications"."verifiable_id" AS verifications_verifiable_id FROM "verifications" GROUP BY "verifications"."verifiable_id"

comments_whose_user_id_is_user_id_or_whose_last_verification_is_approved =
  Comment
    .where(user_id: user_id)
    .or(
      Comment.where(id:
        Comment.joins(:verifications)
          .where(
            verifications: {
              id: latest_verification_ids,
              status: 'approved'
            }
          )
      )
    )

# SELECT "comments".* FROM "comments" WHERE ("comments"."user_id" = ? OR "comments"."id" IN (SELECT "comments"."id" FROM "comments" INNER JOIN "verifications" ON "verifications"."verifiable_id" = "comments"."id" AND "verifications"."verifiable_type" = ? WHERE "verifications"."id" IN (4, 2) AND "verifications"."status" = ?))  [["user_id", 1], ["verifiable_type", "Comment"], ["status", "approved"]]

Rails 5: ActiveRecord 查询加入的最后一个对象 table with OR condition

Rails 5: ActiveRecord query last object in a joined table with OR condition

ruby-on-rails

ruby-on-rails-5

ruby-on-rails-5.1