issue_comments

Demo: https://latest.datasette.io/fixtures/facetable?_facet_array=tags#facet-tags

Challenge: facets can also be defined in metadata.json like this:

{ "databases": { "sf-trees": { "tables": { "Street_Tree_List": { "facets": ["qLegalStatus"] } } } } }

But... ?_facet_array=definitions doesn't fit in that data structure. Need to have an alternative mechanism for defining this kind of facet.

I'm going to go with ?_facet_array=definitions as the querystring argument for this.

And ?definitions_arraycontains=foo as the filter argument.

Note that there doesn't seem to be a way to use indexes (even indexes on expressions) to speed these up, so this will only ever be effective on smaller data sets, probably in the 10,000-100,000 range. Datasette is often used with smaller data sets so this is still worth pursuing.

And here's the query for pulling back every record tagged with a specific tag:

https://latest-code.datasette.io/code-a26fa3c?sql=select+*+from+definitions+where+rowid+in+%28%0D%0A++select+definitions.rowid%0D%0A++from+definitions+join+json_each%28params%29+j%0D%0A++where+j.value+%3D+%3Atag%0D%0A%29&tag=filename

select * from definitions where rowid in ( select definitions.rowid from definitions join json_each(params) j where j.value = :tag )

Example table: https://latest-code.datasette.io/code/definitions

Here's a query that does facet counting against that column:

https://latest-code.datasette.io/code-a26fa3c?sql=select+count%28*%29+as+n%2C+j.value+from+definitions+join+json_each%28params%29+j+group+by+j.value+order+by+n+desc%3B

select count(*) as n, j.value from definitions join json_each(params) j group by j.value order by n desc;