> For the complete documentation index, see [llms.txt](https://simian114.gitbook.io/blog/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://simian114.gitbook.io/blog/undefined/rubyonrails/undefined-3/case-x.md).

# CASE를 이용해서 정렬(일반적인 정렬 X)

{% hint style="info" %}
[**STACKOVERFLOW를 참고하자!**](https://stackoverflow.com/a/66329633)
{% endhint %}

## 상황

길드에는 세 개의 클래스가 존재한다. **master, officer, member**

프론트에서 백엔드에 현재 길드의 유저 정보를 요청하는데, ***그 유저들이 클래스로 정렬되어 있기를 원할 때는 어떻게 해야하는가?***

## 해결

### CASE 를 사용하자!!

실제 사용된 코드는 아래와 같다.

```ruby
def self.priority_order
  self.order(
    # A Relational Algebra
    Arel.sql(<<-SQL.squish
      CASE
      WHEN position = 'master' THEN '1'
      WHEN position = 'officer' THEN '2'
      WHEN position = 'member' THEN '3'
      END
      SQL
      )
    )
end

# 이후에는 아래처럼 사용하면 된다.
def self.for_members_ranking(guild_id, page)
  self.where(guild_id: guild_id).priority_order.page(page).map {                 |membership|
        membership.user.profile
    }
end
```

여기서 주의할 건 `Arel.sql(<<)` 문인데, 이 부분은 레일즈 버전이 업 되면서 추가된 부분이다.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://simian114.gitbook.io/blog/undefined/rubyonrails/undefined-3/case-x.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.