SELECT COUNT(DISTINCT (sessions.visitor_id))                           AS visitors,
       COUNT(*) as views,
       ABS(CEILING(TIMESTAMPDIFF(SECOND, :end, views.viewed_at) / 10)) AS interval_ago
FROM wp_independent_analytics_views as views
         LEFT JOIN wp_independent_analytics_sessions AS sessions
                   ON views.session_id = sessions.session_id
WHERE viewed_at BETWEEN :start AND :end
GROUP BY interval_ago