A problem with this is that if you're using --query you likely want ALL of the results - at the moment the only Datasette output type that can stream everything is .csv and plugin formats can't handle full streams, see #1062 and #1177.

I figured out a neat pattern for streaming JSON arrays in this TIL: https://til.simonwillison.net/python/output-json-array-streaming

Yeah that's a good point. I avoided making them sub-commands because datasette serve already supports the multitude of other arguments they also need... but actually that was just me being lazy - I can easily share arguments between multiple functions like I do in sqlite-utils itself: https://github.com/simonw/sqlite-utils/blob/d1a372b3006e6cf7d2017b3ddc484bf5c033e45d/sqlite_utils/cli.py#L46

(Putting thoughts here to keep the conversation in one place.)

I think using datasette for this use-case is the right approach. I usually have both datasette and sqlite-utils installed in the same project, and that's where I'm trying out queries, so it probably makes the most sense to have datasette also manage the output (and maybe the input, too).

It seems like both --get and --query could work better as subcommands, rather than options, if you're looking at building out a full CLI experience in datasette. It would give a cleaner separation in what you're trying to do and let each have its own dedicated options. So something like this:

```sh

run an arbitrary query

datasette query covid.db "select * from ny_times_us_counties limit 1" --format yaml

run a canned query

datasette get covid.db some-canned-query --format yaml ```

Also relevant: CSV streaming for canned queries in #526 - even better if we could stream ANY SQL query.

A problem with this is that if you're using --query you likely want ALL of the results - at the moment the only Datasette output type that can stream everything is .csv and plugin formats can't handle full streams, see #1062 and #1177.

So there's not much point implementing this unless we first make plugins able to add custom streaming formats.

It's weird that --get is documented on this page right now: https://docs.datasette.io/en/stable/getting_started.html#datasette-get

If I implement this I should build a new "Datasette on the command-line" documentation page to cover both --get and --query.

This is also interesting when used in conjunction with the proposed datasette insert command from #1163 - Datasette would become a plugin-driven CLI tool for both ingesting and outputting data, as a side-effect of its web features.

I should implement #1355 for more efficient --csv streaming as part of this.

This feels like a relatively simple feature to implement that unlocks a whole new set of possible uses for Datasette - as described by @eyeseast in https://github.com/simonw/sqlite-utils/issues/264#issue-907642546.

What happens if you pass multiple databases? The --query would be executed against the first one. And if you pass --crossdb it would be executed against the /_memory database and would support cross-database joins.

Key thing here is that output plugins are supported (also plugins that add new SQL functions), making many Datasette plugins usable from the command-line.