Sounds like a job for the Data Explorer plugin! Very useful, you can learn more about it here:
Here’s a stab at a SQL query that does something like this — it takes trust_level as a parameter, and then returns a sorted list of the # of posts created in each category by users w/ that trust level (disclaimer, I’m a SQL novice, modify as needed!):
-- [params]
-- int :trust_level = 1
WITH topic_categories AS
(SELECT
t.id topic_id,
t.user_id,
t.created_at,
t.score,
c.id category_id,
c.name category_name
FROM
topics t
LEFT JOIN categories c
ON t.category_id = c.id
)
SELECT
count(tc.*) count,
tc.category_id
FROM
users u
LEFT JOIN topic_categories tc
ON u.id = tc.user_id
WHERE
tc.created_at IS NOT NULL
AND tc.category_id IS NOT NULL
AND u.trust_level = :trust_level
GROUP BY
tc.category_id
ORDER BY count DESC
The dashboard won’t specifically include this data. My challenge is to simplify the dashboard but make it useful for all community types. For instance, CoP CMs need very different data to support community CMs. TL data is of very little (if any) relevance to the latter.
What we are planning as a compromise is to surface approved data explorer queries via the dashboard so that mods have access.