> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/reference/sql-commands/sql-dropusermapping.md).

# DROP USER MAPPING

### DROP USER MAPPING

DROP USER MAPPING — remove a user mapping for a foreign server

### Synopsis

```

DROP USER MAPPING [ IF EXISTS ] FOR { user_name | USER | CURRENT_ROLE | CURRENT_USER | PUBLIC } SERVER server_name
```

### Description

`DROP USER MAPPING` removes an existing user mapping from foreign server.

The owner of a foreign server can drop user mappings for that server for any user. Also, a user can drop a user mapping for their own user name if `USAGE` privilege on the server has been granted to the user.

### Parameters

`IF EXISTS` : Do not throw an error if the user mapping does not exist. A notice is issued in this case.

*`user_name`* : User name of the mapping. `CURRENT_ROLE`, `CURRENT_USER`, and `USER` match the name of the current user. `PUBLIC` is used to match all present and future user names in the system.

*`server_name`* : Server name of the user mapping.

### Examples

Drop a user mapping `bob`, server `foo` if it exists:

```

DROP USER MAPPING IF EXISTS FOR bob SERVER foo;
```

### Compatibility

`DROP USER MAPPING` conforms to ISO/IEC 9075-9 (SQL/MED). The `IF EXISTS` clause is a PostgreSQL extension.

### See Also

[CREATE USER MAPPING](/reference/sql-commands/sql-createusermapping.md), [ALTER USER MAPPING](/reference/sql-commands/sql-alterusermapping.md)

***

原文：[PostgreSQL 18.6 Documentation](https://www.postgresql.org/docs/18/sql-dropusermapping.html)（英文原文，待翻譯）


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