显示消息数组中的最后一条消息

本文介绍了显示消息数组中的最后一条消息的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

关于我最后一次尝试的答案，我可以实现自己的目标通缉。应用正常运行后，我发现情况有所不同：仅显示创建消息并发送消息的人。如果我回复，则看不到回复，我知道问题所在。

Regarding my last attempted answer, I could achieve what I wanted. Once the app is working I noticed something is different: only the person that created the message and sends a message was only showing. If I reply, I do not see the reply and I know the problem.

我的消息模型具有表： [：id，：user_id，：to，：body，...]

：user_id 与来自的相似，因为它用于确定谁创建了邮件。

:user_id would be similar to from as that is used to determine who created the message.

用户1 是客户，用户2 是学生。学生向客户发送一条消息。只有我的客户端代码是这样的：

User 1 would be Client and User 2 is Student. Student sends a message to Client. Only my client side the code is as this:

#Controller Index: @messages = Message.where(to: current_user.id) # My replies are not included here .order(user_id: :asc, created_at: :desc) .select('distinct on (user_id) *')

我是说给我发给我的所有邮件（：to ）id 1 。

I'm saying give me all messages that's addressed to me (:to) an id of 1.

我不会看到我的回复，因为：to 列。

I won't see my reply because of the :to column.

我的（客户）回复如下：

to: #student id user_id: #client id

和学生消息：

to: #client id user_id: #student id

因此，由于至现在指向一个id，因此说 2 我看不到答复。我可能需要更改模型，但是如果您看到一种简单的方法，请告诉我。

So because the to now point to an id, let's say 2 I wont see the reply. I may need to change up the model but if you see an easy way, please let me know.

编辑：

有效的答案

@messages = Message.where(to: current_user.id).or(Message.where(user_id: current_user.id)) .order(connection: :desc, created_at: :desc) .select('distinct on (connection) *')

推荐答案

由于您使用的是Rails 5，因此可以利用它的或方法：

Since you are using Rails 5, you can take advantage of it's or method:

Message.where(to: current_user.id).or( Message.where(user_id: current_user.id) ).order(connection: :desc, created_at: :desc) .select('distinct on (connection) *')