Select first and last timestamp where userID is unique

Question

I'm trying to do a query to get first and last timestamp of each unique user.

Database looks like this:

| ID | EventID |      Timestamp      | Person | Number | 
--------------------------------------------------------
| 1  |    2    | 2015-01-08 17:31:40 |   7    |   5    |
| 2  |    2    | 2015-01-08 17:35:40 |   7    |   4    |
| 3  |    2    | 2015-01-08 17:38:40 |   7    |   7    |
--------------------------------------------------------

I'm trying to put together a MySQL query that will do the following:

• SUM of number field for each unique user.
• Time difference (in hours) between first and last row for each unique user. I would imagine that if I could get the first and last timestamp for each user, I should be able to use timediff to get the time difference in hours.

What I've got so far:

SELECT 
  person,
  SUM(number) AS 'numbers_all_sum'
FROM database
WHERE eventid = 2
GROUP BY person
ORDER BY numbers_all_sum DESC

Any help would be greatly appreciated.

Answer 1

Something like this:

SELECT
  Person
  MIN(Timestamp),
  MAX(Timestamp),
  SUM(number) AS 'numbers_all_sum'
FROM database
WHERE eventid = 2
GROUP BY person