> For the complete documentation index, see [llms.txt](https://docs.rasgoml.com/rasgo-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rasgoml.com/rasgo-docs/rasgo-0.1/overview/user-defined-transforms/make-your-own-transform.md).

# Make your own Transform

{% hint style="info" %}
Rasgo uses the [Jinja2 templating engine](https://jinja.palletsprojects.com/en/3.0.x/templates/) and SQL in transform templates.
{% endhint %}

### 1. Create your own Transform template

```django
template = """
SELECT {{ group_by | join(', ') }},
listagg({{ 'distinct ' if distinct else ''}} {{agg_column}}, '{{sep}}')
WITHIN group (order by {{agg_column}} {{order}}) as {{agg_column}}_listagg
FROM {{ source_table }}
GROUP BY {{ group_by | join(', ') }}
"""
```

{% hint style="info" %}
{{ source\_table }} is a required argument in every template, and Rasgo's API will always compile it to the fully-qualified table name (FQTN) of the dataset that the transform is called on.
{% endhint %}

### 2. Publish your Transform template

```python
# Create a new user-defined transform
new_transform = rasgo.create.transform(name="aggregate_string",
                                       source_code=template)
```