View Count of a specific tag

I’m not sure, try this:

-- [params]
-- text :tag_name
SELECT COUNT(tt.tag_id)
FROM topic_tags tt, tags t, topic_views tv, topics tp
WHERE t.id = tt.tag_id
AND tp.id = tt.topic_id
AND tv.topic_id = tp.id 
AND t.name = :tag_name
GROUP BY tt.tag_id