How to compare the first date and the last date?

Question

I have this table:

|NAME(Key)       |     LOGIN_DATE      |
|----------------|---------------------|
|mark            | 2012-10-10 10:35:00 |
|mark            | 2012-10-10 10:40:00 |
|mark            | 2012-10-10 10:45:00 |

I want to know how to find the difference between last and first dates:

|NAME            |     TIME_DIFF       |
|----------------|---------------------|
|mark            | 10 minutes          |

How can I do this?

Answer 1

SELECT name
     , SEC_TO_TIME( MAX(TIME_TO_SEC(login_date))
                  - MIN(TIME_TO_SEC(login_date))
                  ) x 
  FROM my_table 
 GROUP 
    BY name;

Answer 2

select 
    name, 
    concat( timestampdiff( minute,
                           min( login_date ), 
                           max( login_date ) ),
            ' minutes' 
    ) as 'login duration'
from my_table
group by name

Answer 3

SELECT MIN(`LOGIN_DATE`), MAX(`LOGIN_DATE`) WHERE `NAME(Key)` = 'mark';