Get hourly data with gaps from midnight till now

I'm using the code below in order to generate data from midnight till now. SELECT CONCAT(Hour, ':00-', Hour+1, ':00') AS Hours, IFNULL(COUNT(product_id), 0) AS `total_count` FROM clicks RIGHT JOIN ( SELECT 0 AS Hour UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9 UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12 UNION ALL SELECT 13 UNION ALL SELECT 14 UNION ALL SELECT 15 UNION ALL SELECT 16 UNION ALL SELECT 17 UNION ALL SELECT 18 UNION ALL SELECT 19 UNION ALL SELECT 20 UNION ALL SELECT 21 UNION ALL SELECT 22 UNION ALL SELECT 23 ) AS AllHours ON HOUR(clicked_at) = Hour WHERE ( clicked_at BETWEEN CURRENT_DATE() AND NOW() OR clicked_at IS NULL ) AND clicks.site='awesome-site.com' GROUP BY Hour ORDER BY Hour I need the code to return something like Hours total_count ---------------------- 0:00-1:00 19 1:00-2:00 2 2:00-3:00 0 3:00-4:00 0 4:00-5:00 0 5:00-6:00 1 6:00-7:00 0 7:00-8:00 0 8:00-9:00 0 9:00-10:00 4 10:00-11:00 2 11:00-12:00 0 12:00-13:00 17 13:00-14:00 1 The issue is that the query above is return is returning data with gap in the Hours column; something like: Hours total_count ---------------------- 0:00-1:00 19 1:00-2:00 2 5:00-6:00 1 9:00-10:00 4 10:00-11:00 2 12:00-13:00 17 13:00-14:00 1 Thanks for the help.