Question

let’s assume I have this numrequest table. it has these fields: id, id_user, time(timestamp)

I want to count the records for a specific $id_user grouped by week.
I know how to count the records for a period of time.

  $past=time()-$totalSecondsInAweek

  $query='SELECT COUNT(1) as counta
          from numrequest
          WHERE time >'.$past.'
          AND WHERE id_user='.$id_user;

but how to do that so it counts per each week since the first input regarding a specific $id_user

Answer 1

My main doubt, and possible unrelated to the question itself, is why are you doing this?

$past=time()-$totalSecondsInAweek
WHERE time >’.$past.’

Are you trying to get records only from the last 7 days?

If that is the case, please, try this in your sql code:

WHERE time > date_sub(curdate(), INTERVAL 7 DAY)

In my solution I’ll be removing this condition because I don’t understand it and I just can’t link it to grouping by week.

Now, to your answer. My bet is that you don’t want just to group by week. You want to group by the pair (Year-Week). If you don’t do this, you’ll group in the week number 0 both dates: “2011-01-01” and “2012-01-01”. So, I assume you would like to have the previous data displayed this way:

Year | Week | Count(*)
----------------------
2011 | 0    | 1
2012 | 0    | 1

Rather than:

Week | Count(*)
---------------
0    | 2

So, here is the SQL code:

select
    id_user,
    year(time) as AYear, week(time) as AWeek,
    count(*) as TotalPerWeek
from n1
where id_user = 'tim'
group by id_user, AYear, AWeek
order by AYear, AWeek

Here is an example

If you would like to have the year and week in only one column, you can try this (which I think will be faster than a CONCAT(year, week)):

select
    id_user,
    year(time) * 100 + week(time) as YearWeek,
    count(*) as TotalPerWeek
from n1
where id_user = 'tim'
group by id_user, YearWeek
order by YearWeek

Here is an example

Note: If you want your week numbers to start in 0 or to choose whether it should start on monday or sunday check the official documentation.

Hope this helps.