How to count consecutive number of 10 days - mysql

Question

I have table with columns: id, name, date, present
Column present have values 0 or 1 or 2 and ... more
I need to count how many 0 valous is in current month 2013-07-01 - 2013-07-31 but count only when there are or more than 10 times.
for example if i have
2013-07-01 to 2013-07-10 valoues 0 it should count it and let me know that is 10 or more consecutives days like 11, 12 or more, but if it was less than 10 should count nothing.
I was trying some examples from stack... but they are different problems... so i need little help with that mysql query.
i have smth like this but need consecutives 10 days like >= 10
$sql = mysql_query("SELECT COUNT(name) as count FROM `table` WHERE (`present` = 0) AND (`date` BETWEEN '2013-07-01' AND '2013-07-31')");
while($row = mysql_fetch_array($sql)){
$result = $row['count'];
}
It counts me every 0 values in date between 2013-07-01 and 2013-07-31 but i need count how many days start from 10 or more consecutives days
column present have 0 and other numbers like 1, 2, 3... so i need count only 0 with 10 or more consecutives days
here is SqlFiddle i was trying to make warking from answer
http://sqlfiddle.com/#!2/1bde8/2
best regards
m.

Answer 1

This approach uses correlated subqueries to calculate two values.
The first value is the date of the previous record where Present = 1. This allows you to get the number of days in a row where Present = 0 by using datediff().
The second is the Present value of tomorrow, which will be NULL on the last day of the month. When today has Present = 0 and tomorrow is either 1 or NULL, then we can use this record. It is the end of a sequence of 0s.
From there is it just a question of adding up the values according to the conditions that you set. The following query assumes that you want to do this for each name:
select name, sum(case when datediff(date, lastPresentDate) >= 10
then datediff(date, lastPresentDate)
else 0 end) as DaysCounted
from (select t.*,
(select coalesce(max(date), '2013-06-30')
from t t2
where t2.name = t.name and
t2.present <> 0 and
t2.date <= t.date and
t2.date between '2013-07-01' and '2013-07-31'
) as lastPresentDate,
(select t2.present
from t t2
where t2.name = t.name and
t2.date = adddate(t.date, 1)
order by t2.date
limit 1
) as TomorrowPresent
from t
where date between '2013-07-01' and '2013-07-31'
) t
where Present = 0 and (TomorrowPresent = 1 and TomorrowPresent is null)
group by name

Answer 2

This query should give you a count only when it is 10 or greater than 10.
SELECT COUNT(`name`) as `count`
FROM `table`
WHERE (`present` = 0)
AND (`date` BETWEEN '2013-07-01' AND '2013-07-31')
HAVING `count` >= 10;
Hope it helps!

Answer 3

Not tested, but you could use user variables like this:-
SELECT SUM(if(ConsCounter=10, 1, 0))
FROM
(
SELECT id, name, date, present, #Counter := IF(#PrevPresent = present AND present = 0, #Counter + 1, 0) AS ConsCounter, #PrevPresent = present
FROM
(
SELECT id, name, date, present
FROM `table`
ORDER BY date
) Sub1
CROSS JOIN (SELECT #PrevPresent:=-99999, #Counter:=0) Sub2
) Sub4
Get all the records in date order and add a sequence number for the count since the present was first 0. Then count the number of times that counter is 10.