Say you have data like this:

```
  time  value
  10:00   5
  10:15   12
  10:30   15
  10:45   27
  11:00   29

```

And a query like this:

```
SELECT MAX(value) - MIN(value), HOUR(time) FROM mytable GROUP BY HOUR(time);

```

You will get:

```
  value  time
    22    10

```

But, I would need it to include the value at 11:00, thus the result being 24 (29-5), and not 22. Is there a way to do this in SQL or do I have no other choice than to do this manually in the code level (so, without the grouping, just fetching the data and manually subtracting).