Dropdown

A select filter. Its value lands in the reactive filters store under name; any query using ${name} re-runs. Options come from a query column (data + column) or a literal options list. Add multi for a multi-select that feeds an IN (…) clause.

SELECT month, SUM(downloads) AS downloads
FROM downloads
WHERE '${channel}' = '' OR channel = '${channel}'
GROUP BY month
ORDER BY month

Pick a channel — the chart re-queries. The '${channel}' = '' guard makes "no selection" mean "all".

Add multi for a multi-select whose chosen values expand into an IN (…) list (the same empty-means-all guard applies):

SELECT month, SUM(downloads) AS downloads
FROM downloads
WHERE '${channels}' = '' OR channel IN (${channels})
GROUP BY month
ORDER BY month

Attribute	Purpose
`name`	Required. Filter key (the `${name}` your SQL reads).
`data` + `column`	Populate options from a query column.
`options`	…or a literal comma-separated list.
`label`	Control label.
`multi`	Multi-select → `IN (…)`.
`url_sync`	Mirror the value to the URL (default `true`).
`bar`	Lift into the top filter bar (default: inline).

Note

Filter controls drive server-side SQL substitution, so they're stripped from dashdown build static exports (a fixed snapshot can't re-query). See Filters.