Note if you want to count FULL 24h days between 2 dates, datediff can return wrong values for you.
As documentation states:
Only the date parts of the values are used in the calculation.
which results in
select datediff('2016-04-14 11:59:00', '2016-04-13 12:00:00')
returns 1 instead of expected 0.
Solution is using select timestampdiff(DAY, '2016-04-13 11:00:01', '2016-04-14 11:00:00');
(note the opposite order of arguments compared to datediff).
Some examples:
select timestampdiff(DAY, '2016-04-13 11:00:01', '2016-04-14 11:00:00');
returns 0select timestampdiff(DAY, '2016-04-13 11:00:00', '2016-04-14 11:00:00');
returns 1select timestampdiff(DAY, '2016-04-13 11:00:00', now()); returns how many full 24h days has passed since 2016-04-13 11:00:00 until now.Hope it will help someone, because at first it isn't much obvious why datediff returns values which seems to be unexpected or wrong.