Question

How do I check status in where clause?

SELECT `id`,`name`,`start_date`,`end_date`,
CASE
WHEN SYSDATE() <  `start_date` THEN 'WAITING'        
WHEN SYSDATE() >= `start_date` AND SYSDATE() <= `end_date` THEN 'START'
WHEN SYSDATE() >= `end_date`   THEN 'END'
END `status`
FROM teams WHERE `status` = 'START';

When I execute this Query they generate an error like this

See database screenshot also

Answer 1

The problem is that you can’t reference your computed column by name in the same query. So you need to use an inner sub-query:

SELECT `id`,`name`,`start_date`,`end_date`, `status`
FROM (
  SELECT `id`,`name`,`start_date`,`end_date`,
    CASE
      WHEN SYSDATE() <  `start_date` THEN 'WAITING'        
      WHEN SYSDATE() >= `start_date` AND SYSDATE() <= `end_date` THEN 'START'
      WHEN SYSDATE() >= `end_date`   THEN 'END'
    END `status`
  FROM teams) AS T
WHERE `status` = 'START';

Or you can duplicate the logic in your WHERE clause, but most people prefer not to do that. Also note that this solution allows you to simply change your WHERE clause to get the other result sets:

• WHERE status = 'WAITING'
• WHERE status = 'END'

You don’t have to mess around with the logic after it’s set up this way.