Calculate difference between two datetimes in MySQL
If your start and end datetimes are on different days use TIMEDIFF.
SELECT TIMEDIFF(datetime1,datetime2)
if datetime1 > datetime2 then
SELECT TIMEDIFF("2019-02-20 23:46:00","2019-02-19 23:45:00")
gives: 24:01:00
and datetime1 < datetime2
SELECT TIMEDIFF("2019-02-19 23:45:00","2019-02-20 23:46:00")
gives: -24:01:00
my two cents about logic:
syntax is "old date" - :"new date", so:
SELECT TIMESTAMPDIFF(SECOND, '2018-11-15 15:00:00', '2018-11-15 15:00:30')
gives 30,
SELECT TIMESTAMPDIFF(SECOND, '2018-11-15 15:00:55', '2018-11-15 15:00:15')
gives: -40
USE TIMESTAMPDIFF
MySQL function. For example, you can use:
SELECT TIMESTAMPDIFF(SECOND, '2012-06-06 13:13:55', '2012-06-06 15:20:18')
In your case, the third parameter of TIMSTAMPDIFF
function would be the current login time (NOW()
). Second parameter would be the last login time, which is already in the database.