> For the complete documentation index, see [llms.txt](https://docs.mongoing.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mongoing.com/can-kao/yun-suan-fu/query-and-projection-operators/comparison-query-operators/nin.md).

# $nin

**$nin**

*语法*：`{ field: { $nin: [ <value1>, <value2> ... <valueN> ]} }`

`$nin`选择以下位置的文档：

* 该`field`值不在指定的范围内`array` **或**
* 在`field`不存在。

有关不同BSON类型值的比较，请参见指定的BSON比较顺序。

考虑以下查询：

```
db.inventory.find( { qty: { $nin: [ 5, 15 ] } } )
```

这个查询将选择库存集合中`qty`字段值不等于`5`或`15`的所有文档。所选文档将包括那些不包含`qty`字段的文档。

如果字段包含数组，那么`$nin`操作符将选择字段中没有元素等于指定数组中的值的文档(例如`<value1>`， `<value2>`，等等)。

考虑以下查询：

```
db.inventory.update( { tags: { $nin: [ "appliances", "school" ] } }, { $set: { sale: false } } )
```

这个`update()`操作将设置库存集合中的`sale`字段值，其中，`tags`字段包含一个数组，数组中没有与数组`["appliances"， "school"]`中的元素匹配的元素，或者文档不包含`tags`字段。

不等运算符`$nin`的选择性不是很强，因为它经常匹配索引的很大一部分。因此，在许多情况下，带有索引的`$nin`查询的性能可能不比必须扫描集合中所有文档的`$nin`查询好。请参见查询选择性。

> **也可以看看**
>
> `find()`，`update()`，`$set`。

译者：李冠飞

校对：


---

# 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://docs.mongoing.com/can-kao/yun-suan-fu/query-and-projection-operators/comparison-query-operators/nin.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.