> 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-dropcast.md).

# DROP CAST

### DROP CAST

DROP CAST — remove a cast

### Synopsis

```

DROP CAST [ IF EXISTS ] (source_type AS target_type) [ CASCADE | RESTRICT ]
```

### Description

`DROP CAST` removes a previously defined cast.

To be able to drop a cast, you must own the source or the target data type. These are the same privileges that are required to create a cast.

### Parameters

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

*`source_type`* : The name of the source data type of the cast.

*`target_type`* : The name of the target data type of the cast.

`CASCADE`\
`RESTRICT` : These key words do not have any effect, since there are no dependencies on casts.

### Examples

To drop the cast from type `text` to type `int`:

```

DROP CAST (text AS int);
```

### Compatibility

The `DROP CAST` command conforms to the SQL standard.

### See Also

[CREATE CAST](/reference/sql-commands/sql-createcast.md)

***

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


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