Sql date comparison in where clause is not working as expected - mysql

Question

I'm facing a strange mysql behavior...
If I want to return the rows from "MyTable" with a date lower than date-10 seconds ago or a future date
I also store future date because in my real program, I "launch" some queries with delay and date is actually the last query date...i.e.: a kind of queue...:
SELECT (NOW() - date) AS new_delay, id
FROM MyTable
WHERE (NOW() - date < 10)
ORDER BY new_delay DESC;
This one does not work as expected: It returns all the entries:
EDIT: here is the result:
However, this one is working just fine:
SELECT (NOW() - date) AS new_delay, id
FROM MyTable
WHERE (NOW() < date + 10)
ORDER BY new_delay DESC;
DB example:
CREATE TABLE IF NOT EXISTS `MyTable` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`date` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;
INSERT INTO `MyTable` (`id`, `date`) VALUES
(1, (NOW())),
(2, (NOW()-10)),
(3, (NOW()+100));
Any ideas??

Answer 1

Don't do the comparisons like that. In a numeric context now() end up being converted to an integer -- and in an arcane format. Instead, use DATEDIFF() or just regular comparisons. For instance, if you want the difference in days:
SELECT datediff(curdate(), date) as new_delay, id
FROM MyTable
WHERE date >= date_sub(now(), interval 10 day)
ORDER BY new_delay DESC;

Answer 2

use mysql DATEDIFF
select DATEDIFF(curdate(),date) as new_delay, id from MyTable
where date >= date_sub(curdate(), interval 10 day)
ORDER BY new_delay DESC;
DATEDIFF() function returns the time between two dates

Answer 3

As proposed by #Gordon in the his answer, I can use the date_sub / date_add functions...
I can correct the where clause to be :
WHERE NOW() < date_add(ServerRequests.date, interval 10 second)
OR
WHERE date > date_sub(now(), interval 10 second)
OR as proposed in my initial post:
WHERE (NOW() < date + 10)
But I still don't see why I cannot use the sub operation...So if anyone can give me a reason, I would be happy to understand...