feat(coderd): add parameter insights to template insights (#8656)

coderd/database/queries/insights.sql

@@ -114,3 +114,56 @@ SELECT
 	COUNT(DISTINCT user_id) AS active_users
 FROM usage_by_day
 GROUP BY from_, to_;
+
+
+-- name: GetTemplateParameterInsights :many
+-- GetTemplateParameterInsights does for each template in a given timeframe,
+-- look for the latest workspace build (for every workspace) that has been
+-- created in the timeframe and return the aggregate usage counts of parameter
+-- values.
+WITH latest_workspace_builds AS (
+	SELECT
+		wb.id,
+		wbmax.template_id,
+		wb.template_version_id
+	FROM (
+	    SELECT
+	        tv.template_id, wbmax.workspace_id, MAX(wbmax.build_number) as max_build_number
+		FROM workspace_builds wbmax
+		JOIN template_versions tv ON (tv.id = wbmax.template_version_id)
+		WHERE
+			wbmax.created_at >= @start_time::timestamptz
+			AND wbmax.created_at < @end_time::timestamptz
+			AND CASE WHEN COALESCE(array_length(@template_ids::uuid[], 1), 0) > 0 THEN tv.template_id = ANY(@template_ids::uuid[]) ELSE TRUE END
+	    GROUP BY tv.template_id, wbmax.workspace_id
+	) wbmax
+	JOIN workspace_builds wb ON (
+		wb.workspace_id = wbmax.workspace_id
+		AND wb.build_number = wbmax.max_build_number
+	)
+), unique_template_params AS (
+	SELECT
+		ROW_NUMBER() OVER () AS num,
+		array_agg(DISTINCT wb.template_id)::uuid[] AS template_ids,
+		array_agg(wb.id)::uuid[] AS workspace_build_ids,
+		tvp.name,
+		tvp.display_name,
+		tvp.description,
+		tvp.options
+	FROM latest_workspace_builds wb
+	JOIN template_version_parameters tvp ON (tvp.template_version_id = wb.template_version_id)
+	GROUP BY tvp.name, tvp.display_name, tvp.description, tvp.options
+)
+
+SELECT
+	utp.num,
+	utp.template_ids,
+	utp.name,
+	utp.display_name,
+	utp.description,
+	utp.options,
+	wbp.value,
+	COUNT(wbp.value) AS count
+FROM unique_template_params utp
+JOIN workspace_build_parameters wbp ON (utp.workspace_build_ids @> ARRAY[wbp.workspace_build_id] AND utp.name = wbp.name)
+GROUP BY utp.num, utp.name, utp.display_name, utp.description, utp.options, utp.template_ids, wbp.value;