---
metadata:
  - name: generator
    content: Diplodoc Platform v5.50.6
alternate:
  - https://ytsaurus.tech/docs/en/yql/syntax/use.md
  - https://ytsaurus.tech/docs/ru/yql/syntax/use.md
---
> **Documentation Index:** Fetch the complete configuration index at https://ytsaurus.tech/docs/en/llms.txt

# USE

Specifying the "database". As a rule, one of the YTsaurus clusters is used as a database. This database will be used by default to search for tables whenever the database hasn't been specified explicitly.

If the query doesn't include `USE`, then the cluster must be specified at the beginning of the table path in the format ``` cluster.`path/to/table` ``` , for example ``` cluster.`home/yql/test` ```. Backticks are used to automatically escape special characters (in this case, slashes).

Usually the cluster name is specified explicitly, but you can use an expression for it. In this case, `USE` must have the notation ```USE yt:$cluster_name```, where `$cluster_name` is the [named expression](https://ytsaurus.tech/docs/en/yql/syntax/expressions.md#named-nodes) of the `String` type.

Alternatively, you can specify the cluster right at the beginning of the table path in the format ``` yt:$cluster_name.`path/to/table` ```.

In this case, `USE` itself can be used inside [actions](https://ytsaurus.tech/docs/en/yql/syntax/action.md) or [subquery templates](https://ytsaurus.tech/docs/en/yql/syntax/subquery.md). The current cluster value is inherited in the declarations of nested actions or subqueries. The influence area of `USE` stops after the end of the action or subquery template in which it was declared.

#### Examples

```yql
USE <cluster-name>;
```

{% note info "Note" %}

`USE` **doesn't** guarantee that a query will be executed on the specified cluster. A query can be executed on another cluster if no input data are used in it (e.g. ```USE foo; SELECT 2 + 2;```) or if a full path to a table in another cluster is specified (e.g. ``` USE foo; SELECT * FROM bar.`path/to/table`; ```).

{% endnote %}