Question

I have an Intranet site that only registered users can watch videos. Users can watch videos on several platforms like iPhone, iPad, Android or Web and I track all those information (for the simplicity of the problem, please do not consider other platforms). I am trying to display some video watch reports at admin panel.

Table structure is below (I have lots of other columns but they are not important for this problem);

CREATE TABLE IF NOT EXISTS `history` (
  `history_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `video_id` int(11) unsigned NOT NULL,
  `user_id` int(11) unsigned NOT NULL,
  `platform_id` int(11) unsigned NOT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`history_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=9 ;

INSERT INTO `history` (`history_id`, `video_id`, `user_id`, `platform_id`, `created`) VALUES
(1, 1, 1, 1, '2012-05-06 08:13:57'),
(2, 2, 1, 1, '2012-05-06 13:23:57'),
(3, 1, 1, 4, '2012-05-06 18:16:39'),
(4, 4, 2, 3, '2012-05-07 08:14:19'),
(5, 1, 2, 3, '2012-05-07 08:14:55'),
(6, 2, 1, 1, '2012-05-07 15:14:55'),
(7, 3, 2, 1, '2012-05-07 18:05:14'),
(8, 3, 1, 4, '2012-05-07 18:15:24');

CREATE TABLE IF NOT EXISTS `sys_list_of_values` (
  `value_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `display_text` text COLLATE utf8_unicode_ci NOT NULL,
  `list_value` text COLLATE utf8_unicode_ci NOT NULL,
  `list_group` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`value_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=10 ;

INSERT INTO `sys_list_of_values` (`value_id`, `display_text`, `list_value`, `list_group`) VALUES
(1, 'iPhone', 'iphone', 'platform'),
(2, 'Android', 'android', 'platform'),
(3, 'iPad', 'ipad', 'platform'),
(4, 'Website', 'web', 'platform'),
(5, 'Active', 'active', 'status'),
(6, 'Passive', 'passive', 'status'),
(7, 'Waiting for approvement', 'waiting', 'status'),
(8, 'Spam', 'spam', 'status'),
(9, 'Deleted', 'deleted', 'status');

CREATE TABLE IF NOT EXISTS `users` (
  `user_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `username` varchar(80) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=3 ;

INSERT INTO `users` (`user_id`, `username`) VALUES
(1, 'test_user_1'),
(2, 'test_user_2');

CREATE TABLE IF NOT EXISTS `videos` (
  `video_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `user_id` int(11) unsigned NOT NULL,
  `title` varchar(200) COLLATE utf8_unicode_ci NOT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `status` int(11) unsigned NOT NULL,
  PRIMARY KEY (`video_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=5 ;

INSERT INTO `videos` (`video_id`, `user_id`, `title`, `created`, `status`) VALUES
(1, 1, 'Test Video 1', '2012-05-07 08:12:52', 7),
(2, 1, 'Test Video 2', '2012-05-07 08:12:52', 5),
(3, 1, 'Test Video 3', '2012-05-07 08:13:17', 5),
(4, 1, 'Test Video 4', '2012-05-07 08:13:17', 6);

I am trying to display a report like below;

Platform      |     Watch_Count
===============================
iPhone                  20
iPad                     0
Android                  2
Website                120
Total                  142

I have some filter options, like video_id, created, platform etc. For example; I want to display a total watch report for all videos, or for a specific video (video_id), or between dates (created) etc. I also want to display all platforms, whether they are 0 or anything.

The following query displays only iPhone and Website, but I want to display all platforms. If there are no watch count, then it has to be displayed as 0 (zero). I also can’t display a final row which sums all watch_counts and displays a total.

SELECT sys_list_of_values.display_text, COUNT(history.history_id) AS 'total_watch' FROM history
JOIN sys_list_of_values ON sys_list_of_values.value_id = history.platform_id
WHERE history.video_id = 1
AND history.created <  '2012-05-07'
GROUP BY history.platform_id

Answer 1

Retaining your FROM HISTORY, change your JOIN to RIGHT JOIN

SELECT sys_list_of_values.display_text, COUNT(history.history_id) AS 'total_watch' 
FROM history
RIGHT JOIN sys_list_of_values 
   ON sys_list_of_values.value_id = history.platform_id
   AND history.created <  '2012-05-07'
   AND history.video_id = 1

GROUP BY sys_list_of_values.value_id 
order by sys_list_of_values.display_text;

If you want to use LEFT JOIN, switch the places of history and sys_list_of_values:

SELECT sys_list_of_values.display_text, COUNT(history.history_id) AS 'total_watch' 
FROM sys_list_of_values 
LEFT JOIN history
   ON sys_list_of_values.value_id = history.platform_id
   AND history.created <  '2012-05-07'
   AND history.video_id = 1

GROUP BY sys_list_of_values.value_id 
order by sys_list_of_values.display_text;

Live test: http://www.sqlfiddle.com/#!2/495d1/15

---

GROUP BY with ROLLUP is incompatible with ORDER, anyway ROLLUP automatically sorts the list, just remove the ORDER:

SELECT sys_list_of_values.display_text, 
  -- sys_list_of_values.value_id,
  COUNT(history.platform_id) AS 'total_watch' 
FROM sys_list_of_values 
LEFT JOIN history
   ON sys_list_of_values.value_id = history.platform_id
   AND history.created <  '2012-05-07'
   AND history.video_id = 1

where sys_list_of_values.list_group = 'platform'
GROUP BY 
 sys_list_of_values.display_text with rollup

Live test: http://www.sqlfiddle.com/#!2/495d1/68