Question

I have a following table:

+------------+-----------------------------------------------------------------------------------+
| Field      | Type                                                                              |
+------------+-----------------------------------------------------------------------------------+
| id         | int(10) unsigned                                                                  |
| type       | enum('REGISTER','ACTIVATE','LOGIN_SUCCESS','LOGIN_FAIL','LOGOUT','LOCK','UNLOCK') |
| user_id    | int(10) unsigned                                                                  |
| mod_id     | int(10) unsigned                                                                  |
| date       | timestamp                                                                         |
| ip         | int(10) unsigned                                                                  |
| user_agent | text                                                                              |
+------------+-----------------------------------------------------------------------------------+

I am trying to determine, in the simplest possible way (preferably just using MySQL), if there are 3 or more consecutive records with type = LOGIN_FAIL since the last type = LOGIN_SUCCESS or since start of the table.

For example

+----+---------------+---------+--------+---------------------+----+------------+
| id | type          | user_id | mod_id | date                | ip | user_agent |
+----+---------------+---------+--------+---------------------+----+------------+
|  6 | LOGIN_SUCCESS |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  7 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  8 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  9 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
+----+---------------+---------+--------+---------------------+----+------------+

would return TRUE while

+----+---------------+---------+--------+---------------------+----+------------+
| id | type          | user_id | mod_id | date                | ip | user_agent |
+----+---------------+---------+--------+---------------------+----+------------+
|  6 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  7 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  8 | LOGIN_SUCCESS |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
|  9 | LOGIN_FAIL    |       3 |   NULL | 2012-07-21 14:08:32 |  0 | agent      |
+----+---------------+---------+--------+---------------------+----+------------+

would return FALSE. Is it possible to do this with a simple query or do I need to implement this check in some script language?

EDIT: I forgot to mention that this query would have to be limited to a certain user_id but I assume this wouldn’t be a problem.

Otherwise, or even better, would it be possible to count how much records fit this criteria (i.e. how many consecutive type = LOGIN_FAILED records exist since last type=LOGIN_SUCCESS)

Answer 1

SELECT COUNT(*) FROM `table` 
WHERE 
    id > 
        (IFNULL(
            (SELECT id 
            FROM `table` 
            WHERE `type`='LOGIN_SUCCESS' 
            ORDER BY id DESC 
            LIMIT 1),0
        )
    AND `type`='LOGIN_FAIL'

Will get the amount of fails since last success.