Difference Between Dates in MySQL

Find difference between two dates is very easy to find out using simple SQL queries, suppose we want to check,the duration a user logged in.

SELECT 
TIME_TO_SEC( TIMEDIFF( COL_LOGOUT_TIME , COL_LOGIN_TIME ) ) 
AS INTERVAL_IN_SECONDS
FROM Users

Above query will return number of seconds between last logout and login time you can format it using PHP strtotime() and date() functions , COL_LOGOUT_TIME,COL_LOGIN_TIME are column names.

There is another scenario where one may wish to see the number of days since user last logged in.

SELECT 
DATEDIFF(CURDATE(), COL_LOGOUT_TIME) 
AS INTERVAL_IN_DAYS 
FROM Users 

above query will return number of days between current date and COL_LOGOUT_TIME.