Get average time between several dates for one entry

Question

I am not really sure how to explain this, but basically what I am trying to do is get the average time that it takes between a set of dates. This is what the database table looks like

id | offer_id | user |    date    | date_completed
----------------------------------------------------
1  |   123    | test | 1352265988 |   1352265995
2  |   123    | admin| 1352266004 |   1352266022
3  |   123    | kira | 1352264754 |   1352271946

I need to get the average time between the 2 timestamps and calculate them together so I can echo it out in my code. I am sure this would be done with a foreach statement, but I have no idea how to go about doing it. If there is anyone that can point me in the right direction that would be great!

Answer 1

Unless I'm missing something, you can just do it in a single query:

SELECT AVG(date_completed - date)
FROM myTable

Answer 2

Use the SQL-function AVG for each of the colums (date and date_completed). Than, you can just substract each average time and you will get your result you are searching for.