MySQL Count Numbers Are Off - mysql

Question

I am not sure why my numbers are drastically off from each other.
A query with no max id:
SELECT id, DATE_FORMAT(t_stamp, '%Y-%m-%d %H:00:00') as date, COUNT(*) as count
FROM test_ips
WHERE id > 0
AND viewip != ""
GROUP BY HOUR(t_stamp)
ORDER BY t_stamp ASC;
I get:
1 2012-07-18 19:00:00 1313
106 2012-07-18 20:00:00 1567
107 2012-07-19 09:00:00 847
225 2012-07-19 10:00:00 5095
421 2012-07-19 11:00:00 205
423 2012-07-19 12:00:00 900
461 2012-07-19 13:00:00 619
490 2012-07-20 15:00:00 729
575 2012-07-20 16:00:00 1682
1060 2012-07-20 17:00:00 2063
2260 2012-07-20 18:00:00 1417
5859 2012-07-20 21:00:00 1303
7060 2012-07-20 22:00:00 1340
8280 2012-07-20 23:00:00 1211
9149 2012-07-21 00:00:00 1675
10418 2012-07-21 01:00:00 721
11127 2012-07-21 02:00:00 825
But if I add a max id:
AND id <= 8279
I get:
1 2012-07-18 19:00:00 1313
106 2012-07-18 20:00:00 1201
107 2012-07-19 09:00:00 118
225 2012-07-19 10:00:00 196
421 2012-07-19 11:00:00 2
423 2012-07-19 12:00:00 38
461 2012-07-19 13:00:00 20
490 2012-07-20 15:00:00 85
575 2012-07-20 16:00:00 483
1060 2012-07-20 17:00:00 1200
2260 2012-07-20 18:00:00 1200
5859 2012-07-20 21:00:00 1201
7060 2012-07-20 22:00:00 1220
The numbers are WAY off from each other. Something is goofy.
EDIT: Here is my table structure:
id t_stamp bID viewip unique
1 2012-07-18 19:22:20 5 192.168.1.1 1
2 2012-07-18 19:22:21 1 192.168.1.1 1
3 2012-07-18 19:22:22 5 192.168.1.1 0
4 2012-07-18 19:22:22 3 192.168.1.1 1

Answer 1

You are not grouping by ID and I think you intend to.
Try:
SELECT id, DATE_FORMAT(t_stamp, '%Y-%m-%d %H:00:00') as date, COUNT(*) as count
FROM test_ips
WHERE id > 0
AND viewip != ""
GROUP BY id, DATE_FORMAT(t_stamp, '%Y-%m-%d %H:00:00')
ORDER BY t_stamp;

Answer 2

Your query is not consistent.
In your select statement you are displaying the full date.
But you are grouping your data by the hour. So your count statement is taking the count of all the data for each hour of the day.
As an example take your first result:
1 2012-07-18 19:00:00 1313
The count of 1313 contains the records for all of your dates (7/18, 7/19, 7/20, 7/21, 7/22, etc) that have an hour of 19:00.
But the way you have your query setup, it looks like it should be the count of all records for 2012-07-18 19:00:00.
So when you add AND id <= 8279" The dates of 7/21 and some of 7/20 or no longer being counted so your count values are now lower.
I'm guessing you are meaning to group by the date and hour and not just the hour.