Question

所以我试图找到在同一张图片下发表评论的所有用户。

在psql终端中，我写了这个，它为我提供了我需要的所有信息：

    select * from users
inner join comments on users.id = comments.user_id
inner join media on media.id = comments.media_id
where media_id = 1

现在我在Rails中正在这样做：

@users = User.joins(:comments, :media).where(media_id = @medium.id)

我认为哪个应该有效。但是当我尝试在我的视图中打印出@users中的所有用户名时，会抛出此错误：

Association named 'media' was not found on User; perhaps you misspelled it?

我在这里做错了加入条款吗？

DB Schema：

create_table "media", force: true do |t|
    # Unrelevant columns
    t.integer  "user_id"
  end

  add_index "media", ["user_id"], name: "index_media_on_user_id", using: :btree

  create_table "comments", force: true do |t|
    # Unrelevant columns
    t.integer  "user_id",                 null: false
    t.integer  "media_id",                null: false
  end

  add_index "comments", ["media_id"], name: "index_posts_on_media_id", using: :btree
  add_index "comments", ["user_id"], name: "index_posts_on_user_id", using: :btree

  create_table "users", force: true do |t|
    t.string   "name",                   default: "", null: false
  end

Answer 1

由于media与comments而不是users直接相关，您应该：{/ p>

@users = User.joins(comments: :media).where(comments: {media_id: @medium.id})

Rails抛出错误：协会名为＆＃39; media＆＃39;在用户上找不到;也许你拼错了吗？

1 个答案: