DrZTx3T2

11 = complete task (status = completed)
22 = pending task (in the future and not status=completed) 
33 = overdue task (in the past and set to pending)
4	
5CREATE TABLE IF NOT EXISTS `tasks` (
6  `task_id` int(10) NOT NULL AUTO_INCREMENT,
7  `task_date` date DEFAULT NULL,
8  `task_status` enum('pending','approved','complete','cancelled') NOT NULL
9  PRIMARY KEY (`task_id`)
10) ENGINE=MyISAM  DEFAULT CHARSET=utf8;
11	
12SELECT 
13    CASE 
14        WHEN task_status = 'complete' THEN 'Complete Task'
15        WHEN status != 'complete' AND task_date > NOW() THEN 'Pending Task'
16        WHEN status = 'pending' AND task_date < NOW() THEN 'Overdue Task'
17FROM 
18    tasks
19	
20SELECT
21  ...
22  CASE
23    WHEN task_status = 'pending' AND task_date > CURDATE()
24    THEN 'overdue'
25    ELSE task_status
26  END AS task_status,
27  ...
28FROM tasks
29WHERE
30  ...
31	
32SELECT task_id, task_date, 
33  CASE 
34    WHEN task_status = 'complete' THEN 'completed task'
35    WHEN task_status != 'complete' AND task_date > CURDATE() THEN 'pending task'
36    WHEN 
37      (task_status != 'complete' AND task_date <= CURDATE()) 
38      OR (task_status = 'pending') THEN 'pending task'
39  END AS task_status_str
40FROM 
41  tasks