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

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.