---
title: "Function"
sidebarTitle: "Function"
description: "CREATE FUNCTION, SHOW FUNCTIONS, and DROP FUNCTION."
icon: function
keywords: ["create function", "drop function", "show functions", "sql", "udf"]
---

<Badge color="red">Enterprise</Badge> [SQL runs on a deployment.](/sql)

## CREATE FUNCTION {#create}

```sql
CREATE FUNCTION f(x BIGINT) RETURNS BIGINT
LANGUAGE python
AS 'def f(x): return x * 2'
WITH (pip = 'numpy==1.26.4', python_version = '3.11')
```

The body is Python source. Its dependencies are declared with it and are part
of the **immutable function version** -- changing one produces a new version
rather than altering the registered one, so a column filled by an earlier
version is unaffected.

| Option | |
| --- | --- |
| `pip` | pip requirements for the worker environment |
| `conda` | conda packages instead of pip |
| `conda_channels` | channels in priority order; requires `conda` |
| `python_version` | worker Python version, defaulting to yours |
| `gpu` | `'true'` when every execution needs a GPU |

**Errors and limits**

| | |
| --- | --- |
| `LANGUAGE` other than `python` | refused |
| `pip` and `conda` together | refused -- pick one |
| `conda_channels` without `conda` | refused |
| `gpu` set to anything but `'true'` | refused |
| An empty body | refused |
| Any other option | refused, and the message lists what is supported |

<Note>
**Enterprise job type:** `create_function`. Registration returns a job because
the function is baked into an image before the version becomes usable.
</Note>

## SHOW FUNCTIONS {#show}

```sql
SHOW FUNCTIONS
```

Lists registered functions and their versions. Since a version is immutable
and a column pins the version that fills it, this is how you find which
versions are still in use before dropping one.

## DROP FUNCTION {#drop}

```sql
DROP FUNCTION embed WITH (version = '1')
DROP FUNCTION IF EXISTS embed WITH (version = '1')
DROP FUNCTION embed WITH (version = '1', cascade = 'true')
```

`version` is required -- a function is a set of immutable versions, and
dropping is always of one specific version, never "the function" as a whole.

<Warning>
Without `cascade = 'true'`, dropping a version that a column still pins fails
rather than breaking that column silently. Passing it drops the version and
lets columns pinned to it stop refreshing -- they keep their last-filled
values, per [Guarantees](/basics/guarantees#jobs).
</Warning>

## What to read next {#next}

<CardGroup cols={2}>
  <Card title="Function" icon="function" href="/management/function">
    Registering one from the SDK, and diagnosing environment mismatches.
  </Card>
  <Card title="Computed columns" icon="table-columns" href="/feature-engineering/add-computed-column">
    Filling a column with a function instead of an expression.
  </Card>
</CardGroup>