Question

I have a table like below:

uid nid     points  date                        reason
36  116     2       2012-08-28 11:52:12         session
31  110     2       2012-08-23 15:47:47         session
36  115     2       2012-08-27 11:52:48         session

as u can see uid is not unique, it can be repeated. What i need is to select sum of points for every id between date(30 days before). For example: sum of uid36 = to 4.
What i have tried:

$start_time = mktime(0, 0, 0, $today["mon"], ($today["mday"] - 30), $today["year"]);//30 days before
$end_time = time();
$query = db_query("SELECT uid,sum(points), date FROM users_history WHERE date BETWEEN '$start_time' AND '$end_time'");

but how to select for every id

Answer 1

You need GROUP BY uid, and date is meanless in your query if you are using aggregate function SUM.

SELECT uid, SUM(points) 
FROM users_history 
WHERE date BETWEEN DATE_SUB(CURDATE(), INTERVAL 30 day) AND NOW() 
GROUP BY uid

And if there is no future date, then you only need

WHERE date >= DATE_SUB(CURDATE(), INTERVAL 30 day)