Hourly activity breakdown (since arbitrary date)

SQL

SELECT   CONCAT(Hour, ':00-', Hour+1, ':00') AS Hours
  ,      COUNT(rc_timestamp) AS `usage`
FROM     recentchanges
  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(rc_timestamp) = Hour
WHERE    rc_timestamp > 20150110215640
GROUP BY Hour
ORDER BY Hour
SQL

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