# Page Not Found

The URL `12.-quan-wen-jian-suo/12.4.-yan-shen-gong-neng` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [12.4. 延伸功能](https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo/12.4.-yan-shen-gong-neng.md)
- [12.3. 細部控制](https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo/12.3.-xi-bu-kong-zhi.md)
- [12.11. 功能限制](https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo/12.11.-gong-neng-xian-zhi.md)
- [12.2. 查詢與索引](https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo/12.2.-cha-xun-yu-suo-yin.md)
- [12. 全文檢索](https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://docs.postgresql.tw/16/the-sql-language/12.-quan-wen-jian-suo/12.4.-yan-shen-gong-neng.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://docs.postgresql.tw/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://docs.postgresql.tw/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/16/the-sql-language/12.-quan-wen-jian-suo/12.4.-yan-shen-gong-neng.md`).

You may also use `Accept: text/markdown` header for content negotiation.