Question

Say i have this table:

+----+------+---------------------+-------------------------+
| id | user | timestamp           | referrer                |
+----+------+---------------------+-------------------------+
| 1  | foo  | 2012-08-26 14:05:55 | http://fubar.com/online |
+----+------+---------------------+-------------------------+
| 2  | foo  | 2012-08-26 14:05:59 | http://fubar.com/chat   |
+----+------+---------------------+-------------------------+
| 3  | bar  | 2012-08-27 07:06:07 | http://fubar.com/chat   |
+----+------+---------------------+-------------------------+
| 4  | max  | 2012-08-28 14:08:12 | http://fubar.com/chat   |
+----+------+---------------------+-------------------------+
| 5  | max  | 2012-08-28 14:08:36 | http://fubar.com/online |
+----+------+---------------------+-------------------------+

i want to select all users who has both more than 1 referrer and timestamps are the same up to the minute precision

this would mean that during a span of 1 minute, they were viewing 2 pages of the same site and thus could imply that they are multi-tabbing. so in the table above, foo and max would fit the criteria.

i want to know how i can achieve this in mysql.

thank you.

Answer 1

Make a self-join and use TIMESTAMPDIFF() in the join cirteria:

SELECT DISTINCT a.user
FROM   my_table a JOIN my_table b ON
       a.user     =  b.user
   AND a.id       <  b.id
   AND a.referrer <> b.referrer
   AND ABS(TIMESTAMPDIFF(SECOND, a.timestamp, b.timestamp)) <= 60

See it on sqlfiddle.