It would be really cool if you could register additional custom SQL functions for use with the sqlite-utils query command - something like this:

``` sqlite-utils data.db 'update images set domain = extract_domain(url)' --functions ' from urllib.parse import urlparse

def extract_domain(url): return urlparse(url).netloc ' ``` Every function defined in that code block would be registered with the connection, unless the name began with an underscore.

https://github.com/simonw/sqlite-utils/compare/3.28...104f37fa4d2e7e5999c1d829267b62c737f74d3e

Suggested by @jefftriplett on Discord: https://discord.com/channels/823971286308356157/997738192360964156/1011655389063958600

Work in progress. Still needs documentation and tests (and to cover more cases of things that might have changed).

Refs: - #467

:books: Documentation preview :books:: https://sqlite-utils--468.org.readthedocs.build/en/468/

Interesting challenge with default_value: I need to be able to tell if the default values passed to .create() differ from those in the database already.

Introspecting that is a bit tricky:

```pycon

import sqlite_utils db = sqlite_utils.Database(memory=True) db["blah"].create({"id": int, "name": str}, not_null=("name",), defaults={"name": "bob"}) <Table blah (id, name)> db["blah"].columns [Column(cid=0, name='id', type='INTEGER', notnull=0, default_value=None, is_pk=0), Column(cid=1, name='name', type='TEXT', notnull=1, default_value="'bob'", is_pk=0)] `` Note how a default value of the Python stringbobis represented in the results ofPRAGMA table_info()asdefault_value="'bob'"` - it's got single quotes added to it!

So comparing default values from introspecting the database needs me to first parse that syntax. This may require a new table introspection method.

Originally posted by @simonw in https://github.com/simonw/sqlite-utils/issues/468#issuecomment-1229279539

Imitate: - https://github.com/simonw/datasette/pull/1789 ```

would load default entrypoint like before

datasette data.db --load-extension ext

loads the extensions with the "sqlite3_foo_init" entrpoint

datasette data.db --load-extension ext:sqlite3_foo_init

loads the extensions with the "sqlite3_bar_init" entrpoint

datasette data.db --load-extension ext:sqlite3_bar_init ```

I figured out a workaround for the ugly global x hack here: - https://github.com/simonw/sqlite-utils/issues/471#issuecomment-1229120653

For consistency with search: https://sqlite-utils.datasette.io/en/stable/cli-reference.html#search

-o, --order TEXT Order by ('column' or 'column desc')

I wanted to run sqlite-utils rows db.db mytable --order 'rowid desc' to see the most recently imported rows.

In this example:

```python @db.register_function def reverse_string(s): return "".join(reversed(list(s)))

print(db.execute('select reverse_string("hello")').fetchone()[0])

``` There's currently no way to over-ride the automatically selected name for the SQL function.

Also testing https://docs.readthedocs.io/en/stable/pull-requests.html