Count consecutive rows with a particular status - mysql

Question

I need to count whether there are three consecutive failed login attempts of the user in last one hour.
For example
id userid status logindate
1 1 0 2014-08-28 10:00:00
2 1 1 2014-08-28 10:10:35
3 1 0 2014-08-28 10:30:00
4 1 0 2014-08-28 10:40:00
In the above example, status 0 means failed attempt and 1 means successful attempt.
I need a query that will count three consecutive records of a user with status 0 occurred in last one hour.
I tried below query
SELECT COUNT( * ) AS total, Temp.status
FROM (
SELECT a.status, MAX( a.id ) AS idlimit
FROM loginAttempts a
GROUP BY a.status
ORDER BY MAX( a.id ) DESC
) AS Temp
JOIN loginAttempts t ON Temp.idlimit < t.id
HAVING total >1
Result:
total status
2 1
I don't know why it display status as 1. I also need to add a where condition on logindate and status field but don't know how would it work

Answer 1

For consecutive count you can use user defined variables to note the series values ,like in below query i have use #g and #r variable, in inner query i am storing the current status value that could be 1/0 and in case expression i am comparing the value stored in #g with the status column if they both are equal like #g is holding previous row value and previous row's status is equal to the current row's status then do not change the value stored in #r,if these values don't match like #g <> a.status then increment #r with 1, one thing to note i am using order by with id column and assuming it is set to auto_increment so for consecutive 1s #r value will be same like #r was 3 for first status 1 and the again status is 1 so #r will 3 until the status changes to 0 same for status 0 vice versa
SELECT t.userid,t.consecutive,t.status,COUNT(1) consecutive_count
FROM (
SELECT a.* ,
#r:= CASE WHEN #g = a.status THEN #r ELSE #r + 1 END consecutive,
#g:= a.status g
FROM attempts a
CROSS JOIN (SELECT #g:=2, #r:=0) t1
WHERE a.`logindate` BETWEEN '2014-08-28 10:00:00' AND '2014-08-28 11:00:00'
ORDER BY id
) t
GROUP BY t.userid,t.consecutive,t.status
HAVING consecutive_count >= 3 AND t.status = 0
Now in parent query i am grouping results by userid the resultant value of case expression i have name is it as consecutive and status to get the count for each user's consecutive status
One thing to note for above query that its necessary to provide the
hour range like i have used between without this it will be more
difficult to find exactly 3 consecutive statuses with in an hour
Sample data
INSERT INTO attempts
(`id`, `userid`, `status`, `logindate`)
VALUES
(1, 1, 0, '2014-08-28 10:00:00'),
(2, 1, 1, '2014-08-28 10:10:35'),
(3, 1, 0, '2014-08-28 10:30:00'),
(4, 1, 0, '2014-08-28 10:40:00'),
(5, 1, 0, '2014-08-28 10:50:00'),
(6, 2, 0, '2014-08-28 10:00:00'),
(7, 2, 0, '2014-08-28 10:10:35'),
(8, 2, 0, '2014-08-28 10:30:00'),
(9, 2, 1, '2014-08-28 10:40:00'),
(10, 2, 1, '2014-08-28 10:50:00')
;
As you can see from id 3 to 5 you can see consecutive 0s for userid 1 and similarly id 6 to 8 userid 2 has consecutive 0s and they are in an hour range using above query you can have results as below
userid consecutive status consecutive_count
------ ----------- ------ -------------------
1 2 0 3
2 2 0 3
Fiddle Demo

Answer 2

M Khalid Junaid's answer is great, but his Fiddle Demo didn't work for me when I clicked it.
Here is a Fiddle Demo which works as of this writing.
In case it doesn't work later, I used the following in the schema:
CREATE TABLE attempts
(`id` int, `userid` int, `status` int, `logindate` datetime);
INSERT INTO attempts
(`id`, `userid`, `status`, `logindate`)
VALUES
(1, 1, 0, '2014-08-28 10:00:00'),
(2, 1, 1, '2014-08-28 10:10:35'),
(3, 1, 0, '2014-08-28 10:30:00'),
(4, 1, 0, '2014-08-28 10:40:00'),
(5, 1, 0, '2014-08-28 10:50:00'),
(6, 2, 0, '2014-08-28 10:00:00'),
(7, 2, 0, '2014-08-28 10:10:35'),
(8, 2, 0, '2014-08-28 10:30:00'),
(9, 2, 1, '2014-08-28 10:40:00'),
(10, 2, 1, '2014-08-28 10:50:00')
;
And this as the query:
SELECT t.userid,t.consecutive,t.status,COUNT(1) consecutive_count
FROM (
SELECT a.* ,
#r:= CASE WHEN #g = a.status THEN #r ELSE #r + 1 END consecutive,
#g:= a.status g
FROM attempts a
CROSS JOIN (SELECT #g:=2, #r:=0) t1
WHERE a.`logindate` BETWEEN '2014-08-28 10:00:00' AND '2014-08-28 11:00:00'
ORDER BY id
) t
GROUP BY t.userid,t.consecutive,t.status
HAVING consecutive_count >= 3 AND t.status = 0;