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Brendan Clement
e20664740f
The two Function pages declare `launch: functions`, and every other page marks what it says about Functions, so the assembled site leaves them out until the launch. Before it, the pages that offered Functions for Python work point Enterprise readers at Geneva instead. The SQL Function example now uses Arrow type names, which the server requires, and states the 3.12 default for `python_version`.
93 lines
3.1 KiB
Plaintext
93 lines
3.1 KiB
Plaintext
---
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title: "Function"
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sidebarTitle: "Function"
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description: "CREATE FUNCTION, SHOW FUNCTIONS, and DROP FUNCTION."
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icon: function
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keywords: ["create function", "drop function", "show functions", "sql", "udf"]
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launch: functions
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---
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<Badge color="red">Enterprise</Badge> [SQL runs on a deployment.](/sql)
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## CREATE FUNCTION {#create}
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```sql
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CREATE FUNCTION f(x int64) RETURNS int64
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LANGUAGE python
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AS 'def f(x): return x * 2'
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WITH (pip = 'numpy==1.26.4', python_version = '3.11')
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```
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Parameter and result types are Arrow type names, not SQL ones: `int64`,
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`float64`, `utf8`, `bool`, `date32`, and lists such as `list<float32>` or
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`fixed_size_list<float32, 768>`. `BIGINT` is refused. A parameter accepts nulls
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unless it is declared `NOT NULL`.
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The body is Python source. Its dependencies are declared with it and are part
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of the **immutable function version** -- changing one produces a new version
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rather than altering the registered one, so a column filled by an earlier
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version is unaffected.
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| Option | |
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| --- | --- |
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| `pip` | pip requirements for the worker environment |
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| `conda` | conda packages instead of pip |
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| `conda_channels` | channels in priority order; requires `conda` |
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| `python_version` | worker Python version; `3.12` when omitted, whatever Python you send the statement from |
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| `gpu` | `'true'` when every execution needs a GPU |
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**Errors and limits**
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| --- | --- |
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| `LANGUAGE` other than `python` | refused |
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| `pip` and `conda` together | refused -- pick one |
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| `conda_channels` without `conda` | refused |
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| `gpu` set to anything but `'true'` | refused |
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| An empty body | refused |
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| Any other option | refused, and the message lists what is supported |
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<Note>
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**Enterprise job type:** `create_function`. Registration returns a job because
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the function is baked into an image before the version becomes usable.
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</Note>
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## SHOW FUNCTIONS {#show}
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```sql
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SHOW FUNCTIONS
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```
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Lists registered functions and their versions. Since a version is immutable
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and a column pins the version that fills it, this is how you find which
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versions are still in use before dropping one.
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## DROP FUNCTION {#drop}
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```sql
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DROP FUNCTION embed WITH (version = '1')
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DROP FUNCTION IF EXISTS embed WITH (version = '1')
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DROP FUNCTION embed WITH (version = '1', cascade = 'true')
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```
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`version` is required -- a function is a set of immutable versions, and
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dropping is always of one specific version, never "the function" as a whole.
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<Warning>
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Without `cascade = 'true'`, dropping a version that a column still pins fails
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rather than breaking that column silently. Passing it drops the version and
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lets columns pinned to it stop refreshing -- they keep their last-filled
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values, per [Guarantees](/basics/guarantees#jobs).
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</Warning>
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## What to read next {#next}
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<CardGroup cols={2}>
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<Card title="Function" icon="function" href="/management/function">
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Registering one from the SDK, and diagnosing environment mismatches.
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</Card>
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<Card title="Computed columns" icon="table-columns" href="/feature-engineering/add-computed-column">
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Filling a column with a function instead of an expression.
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</Card>
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</CardGroup>
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