MySQL - select data from database between two dates

Question

I have saved the dates of a user\'s registration as a datetime, so that\'s for instance 2011-12-06 10:45:36. I have run this query and I expected this item

Answer 1

You need to use '2011-12-07' as the end point as a date without a time default to time 00:00:00.

So what you have actually written is interpreted as:

 SELECT users.* 
 FROM   users
 WHERE  created_at >= '2011-12-01 00:00:00' 
   AND  created_at <= '2011-12-06 00:00:00'

And your time stamp is: 2011-12-06 10:45:36 which is not between those points.
Change this too:

 SELECT users.* 
 FROM   users
 WHERE  created_at >= '2011-12-01'  -- Implied 00:00:00
   AND  created_at <  '2011-12-07'  -- Implied 00:00:00 and smaller than 
                                   --                  thus any time on 06

Answer 2

Your problem is that the short version of dates uses midnight as the default. So your query is actually:

SELECT users.* FROM users 
WHERE created_at >= '2011-12-01 00:00:00' 
AND created_at <= '2011-12-06 00:00:00'

This is why you aren't seeing the record for 10:45.

Change it to:

SELECT users.* FROM users 
WHERE created_at >= '2011-12-01' 
AND created_at <= '2011-12-07'

You can also use:

SELECT users.* from users 
WHERE created_at >= '2011-12-01' 
AND created_at <= date_add('2011-12-01', INTERVAL 7 DAY)

Which will select all users in the same interval you are looking for.

You might also find the BETWEEN operator more readable:

SELECT users.* from users 
WHERE created_at BETWEEN('2011-12-01', date_add('2011-12-01', INTERVAL 7 DAY));