Hello and welcome @CarrieSeltzer 
Would something like this work for you?
-- [params]
-- int :category_id
WITH tag_names AS (
SELECT t.id topic_id,
string_agg(tags.name, ', ' ORDER BY tags.name) AS "tags"
FROM topics t
JOIN topic_tags tt ON tt.topic_id = t.id
JOIN tags ON tags.id = tt.tag_id
GROUP BY t.id
)
SELECT t.created_at::date,
dvtvc.topic_id,
votes_count,
t.posts_count,
tn.tags,
t.closed
FROM discourse_voting_topic_vote_count dvtvc
JOIN topics t ON t.id = dvtvc.topic_id
LEFT JOIN tag_names tn ON dvtvc.topic_id = tn.topic_id
WHERE t.category_id = :category_id
AND votes_count > 0
ORDER BY t.created_at DESC
